Combat re-think for the announced big rebalance [OFLGBKYBYGT]

[deprav]

TL;DR : There's no TL;DR, you have to read the whole thing ! Lazy motherlover !

First, lets take a look at what's wrong, in my opinion :
Today, after a few months of not playing MP, I played again with my gf to take a look at the new lag-fix of 29.3 [which is working pretty nicely!]. And after a while, thinking about the recent OFLGBKYBYGT announcement, I had a strong feeling that combat is actually far from the fun it could be. It's actually too slow and repetitive, we don't really feel the emergency, the danger of the confrontation. Like earlier, we had a group of 3 players, zombies were being knocked back by 10 feet and we actually chased their stumbling to land a knock-down blow and finished them on the ground. I feel more like a threat for zombies than them being a threat for me.

Considering the announcement of the beginner mode and the desire of TiS to redirect the game toward a more "hardcore" feeling, I thought actual combat could turn into something faster paced, something we could define as more "arcade-ish" (Don't "boo" yet).
With its game design choices, project zomboid is aiming to be an ultra-realistic depiction of a zombie-apocalyptic world -which it's doing awesomely- but will never have a realistic combat mechanic : we can't aim for the legs to make the Zeds kneel and bash their head in, we can't chop their limbs/head off, we can't make kung fu moves, we can't takedown on the ground and finish with a knife it the eye etc... the game is not built to have a realistic combat simulation.
So why not accepting it completely and free the combat system from its "realistic constraints" to make it more fun & more stressful in a old-school arcade-game way, like side-scrolling shoot'em ups or asteroids in which the punition for letting yourself being touched by the ennemy is instant and expeditive : you die.

I think that's one of the things missing from PZ zombie-fighting : from the very moment a zed touches you, the punition should be instant !! Whereas now, you can leave your keyboard & mouse for 5 or 10 seconds (even more online) with zombies massaging your face, without necessarily being injured, scratched, or bitten. You can even survive 3 zeds getting a hold on you just by walking away from their grab, or you can open a door and enter carelessly, head-on INTO a group of zeds and walk away, alive...
All of which leads to turn outside journeys and adventures into quiet walks in the street, with a few heated moment of "slow" combat. I think we should be scared of being outside of our "safe" place, constantly in the fear of drawing their attention, always having doubts when opening doors ("what if one's behind and grabs my character as soon as I enter"), always on edge.



So... concretely what to change gameplay wise ? How to make it more hardcore-ish and interesting ? it should stay very close from the actual one with a few twists :

• Make the combat stance a toggle on/off thingy instead of holding RMB + click LMB to attack, so you can have RMB and LMB completeley separated. (combat stance = looking around with your mouse, holding weapon ready to attack).
  With combat stance on :
  • LMB becomes the attack, you still have to hold it to generate a real blow and release the hit. It matches the "accuracy" skill : the higher your accuracy level is, the more damages you make and the less time you need to hold your attack.
  • RMB becomes the defense/shove, It matches the "guard" skill : the higher your guard skill is, the more powerful the shove/defend becomes, giving you more breathing time when pushing them away, and breaking grabs faster.
    How would defense work ? if a zombie gets passed the sweet-spot of your weapon you need to defend by pressing RMB instantly, before its hands reach you, before it's too late... If you fail to defend, or mess up and click LMB instead of RMB : critical miss, the zombie grabs you, which means you WILL get scratched** when you break the grab, also you're totally immobilized which gives time for more zeds to come. If two zeds grab you, it's a bite, 95% chance of zombification, slow death. If three (or more) zeds grab you, you're getting eaten alive right on the spot, no 5% of hope, you scream as you watch pieces of yourself getting ripped appart :3
  • Breaking the grab would work like the normal hold attack mechanic, but you'd have to hold defense when grabbed, and release to push the zombie away. If you fail to charge it in time, you're bitten.

**Scratches have a low chance of zombifying you, but a VERY HIGH chance of developping a classic wound infection if not disinfected and bandaged during the following 12h. Scratches = Death if not cared quickly.
 
So to resume : well timed attack > if failed attack > defend > if failed defense > grabbed (scratched) > if failed break (bitten) > dead.
It has to be quick and unforgiving.

• (always in combat stance) decrease the backpedalling speed so you can't attack and backpedal faster than the zombies are coming to you.
   
• zombies need to stumble much less further when hit or pushed, in a first time - and the distance and knock-down chances would increase gradually, depending on your accuracy & guard level.

Add to all this the comeback of huge hordes and a general larger amount of zeds ; you have a difficult, but yet simplistic, combat system that keeps the player focused and on his guards at all time ! The one we've always craved for ;o
That's when we'll find the real use for sneaking and the sneaking overhaul, when we'll be scared to fight. Travelling from point A to point B should either be a sneaking challenge, or a tactical group work, or an epic "fight your way through" ; but it should never (or very rarely, in deep country areas) be a calm walk like it is right now. It's so calm that when I travel from Muldraugh to Westpoint, I just run straight in the middle of the road, not even paying attention to the zeds on the way, playing only with the keyboard hand as I know even bumping into one of the them won't have any effect.



Also, a few down-the-road positive effects of that suggestion :
The attack / defense system opens the door for a pretty fun PVP melee system based on attack / defense timings and character's skills.
The defend RMB could also become the "take cover" action when holding a firearm, since I know it's planned for the future.
Making a distinct combat stance mode will prevent unvoluntary hits on doors (we all hate those), and prepare the future sneaking overhaul, since combat and sneaking needs to be clearly separated.

[syfy]

interesting idea, but as i've said before.......don't just assume everyone will be playing using the Mouse/Keyboard combo. as Controller support continues to advance, a lot more people will most likely switch over.

[Slendy]

Too.. much to read.

[deprav]

interesting idea, but as i've said before.......don't just assume everyone will be playing using the Mouse/Keyboard combo. as Controller support continues to advance, a lot more people will most likely switch over.

Indeed ! that's why the system I suggest is still working with only 2 buttons, just like the actual one. The mechanics have to be simplistic, but the gameplay must not be simple !

Imo, the actual "hold a button and press another one to attack" mechanic is probably worst with a controller.

[Gou]

Maybe you could just turn up the zombie settings? Also hello, I'm new.

[deprav]

Maybe you could just turn up the zombie settings? Also hello, I'm new.

Welcome to the forums !

turning up the zombie settings is very likely to happen as well (at least their numbers, probably their senses), but the combat would still need some improvements not to stay the not-so-fun wonky mechanics we currently have.

Also, I forgot to say something pretty important in the OP :

The introduction of 2 different combat actions (attack / defense) is a big step toward a more stressful combat system ! why ? because offering the player 2 possibilites is giving him the possibility to make mistakes, in contradiction with the actual 1 button system which plays both attack & defense actions, depending on the zombies distance from the player. That current system gives almost no room for mistakes, it's practically impossible to fail !

 

[Comrade Crimson]

I also think zombies should be more of an actual object, more solid to speak- I should NOT be able to run through a crowd of them and only being slowed down briefly. I should be bumping into them, getting moshed and then violently mobbed by them, zombies should not be easy to run through if they are clumped together and I think a collision system would fix a lot of the problems of the game being too easy off the bat.

[EnigmaGrey]

So why not accepting it completely and free the combat system from its "realistic constraints" to make it more fun & more stressful in a old-school arcade-game way, like side-scrolling shoot'em ups or asteroids in which the punition for letting yourself being touched by the ennemy is instant and expeditive : you die.

The game isn't Mario and it doesn't provide you with a series of lives and the ability to replenish them.

Instead you invest in a character and try to grow them during their final days in the zombie apocalypse. It'd sort of knee-cap that vibe if simply getting close to a zombie, any zombie, was instantaneous death.

 

Whereas now, you can leave your keyboard & mouse for 5 or 10 seconds (even more online) with zombies massaging your face, without necessarily being injured, scratched, or bitten.

You cannot. If you let the zombie complete its animation, it's bitten or scratched you. In multiplayer, the lack there-of could be lag, unfortunately.

Hopefully, the default animation will one day be replaced with something of varying length, but it's not 5-10 seconds.

 

You can even survive 3 zeds getting a hold on you just by walking away from their grab, or you can open a door and enter carelessly, head-on INTO a group of zeds and walk away, alive...

Three should be immobilizing you (or reducing your speed to anguishing crawl) in the current game unless you shove them and fight them to get away (and even that isn't often possible).

The door thing itself seems to be a bug: while zombies "fade in" they don't appear to react to the player.

Having a dedicated melee shove would be great, assuming it isn't as powerful as the current version (or if it's relatively random in its power). You can see this has already been added to some weapons as an automatic trigger, if a zombie is too close, but having it be controllable could make for some interesting situations.

Edit: Rereading what I've wrote here it looks like I'm against the majority of your post, Deprav. I'm not. Your combat suggestions themselves are pretty good. It's the justification for them that I disagree with.

[deprav]

-zlopd-

 

Yeah I think I see what you mean when you say you disagree with the justification, I kinda over emphasized the issues to expose my point and used extreme counter-exemples to describe what I meant by "old-school arcade game way"

Of course I don't want insta death at the very moment a zombie reaches your character, but I wanted to point out the fact that "punishements" (injuries, scratches, not necessarily a straight bite & death) were inflicted too slowly when a zombie is in "hurting range". Plus, zombies are pretty slow, which means it's not that hard to see them coming before they can touch you. Hence the justified insta punishement for doing so.

Also, you're probably right about lags in MP making the injuries even slower. I did make a test and bringed a big group of zeds on me, and didn't touch my keyboard and mouse, I'm not lying when I say I waited approximatively 10 seconds, without any scratch or bite, while I wasn't opposing ANY resistance. My health was slowly going down like they were trying to punch me, but the first serious injuries came as my health bar was already at 1/3 of its full capacity.

It happens in SP as well, but on a way less dramatic scale.

Now that I think about it, it might be a bug created by the zombies "repulsion field" when there are too many of them attacking you. Like when they attack in a big group and you stop moving, you can see your character being pushed away from them, as all their "repulsion fields" must be driving you out of reach of their attacks. That's probably a part of the problem, but I think the "instant punishement" (mandatory scratch when grabbed, bitten if grabbed for too long) could fix it, since there would be no delay to be messed up / restarted by any other factor.

 The tricky parts would be passing corners and opening doors, stressful situations <3

[EnigmaGrey]

Long time ago now, I took this image just after zombies were made capable of pushing the player:

If it's saving you, it's a definite bug. But, again, I've observed this in mulitiplayer myself, so I know where you're coming from, re: repulsion.

[deprav]

If I'm not mistaken, the repulsive field is the way they're simulating the collisions with zombies for the moment. But maybe they saw it the wrong way ? Instead of simulating the collision with a repulsive field, maybe they should simulate it with a "pulling field". That way, when you happen to run into a zombie, instead of being pushed away from its already limited range of action, you'd be pulled in and slowed down, emphasizing the grab, since it does need some improvement as well.

And goodbye injuries taking ages to be inflicted, goodbye passing through a group of zeds blocking a door, it would feel like trying to make your way through a compact crowd.

[Slendy]

Um.. question, anyone else been having ping issues with build 28?

[bvhv]

I don't know about you guys but 5 zombies in their hand range = impossible to escape without sprinting level 2... Many times have i saved my friends only to get caught up by the zombies and torn to death...

[deprav]

Um.. question, anyone else been having ping issues with build 28?

xD That's not really the thread to ask that question but yes, build 28 and anteriors lag a lot. If you want to be lag free I suggest you use the IWBUMS 29.3 in which they fixed the big lag spikes when other players connect, and less lags in general.

 

 

I don't know about you guys but 5 zombies in their hand range = impossible to escape without sprinting level 2... Many times have i saved my friends only to get caught up by the zombies and torn to death...

It sounds very likely yeah, but it's as well likely to survive 5 zombies in MP. A buddy from another game bought PZ to play with me a few days ago. He had his first experience with PZ on MP (he was the 3rd guy of the group I'm mentionning in the OP), he was almost clueless about the combat mechanics and I saw him surviving 4/5 zombies, as he wasn't even moving, just holding RMB and spamming LMB, standing still like a rock. He eventually got away when I told him to move.

3/4 zombies at hand range should be mandatory death if you're not being helped by other survivors, even more for a beginner with 0 combat skill !

Think about it that way : in a real life situation, if a zombie grabs you and try to pull you to his mouth, you either have to kill it or make it let go very soon, or you'll hand up using both your arms and all your strenght to resist the pull. So, if you're focused on not getting bitten and using both your arms already, how will you be able to deal with that second zombies incoming on your left? and that third one incoming from your right... Unless you took care of the first one before the 2nd one reaches your arms range, you're pretty much dead.

Hence the "grabbed by one zombie  = scratched ; grabbed by 2 zombies = bitten ; 3+ zombies = eaten on the spot".

Also, I don't think I precised it in the previous posts, but if a zombie reaches you and you have your guard down or do not react/oppose any resistance in time, you should get bitten.

I'm saying it again but that's very important for a judicious balance : Zombies are slow to move, players already have plenty of time to see them coming before they reach him. And if a player is careless enough to let zombies hug him without being ready to fight, his character deserves to die !

[Slendy]

Alright

[MrBlackAttack]

I actually agree with most of the points that deprav made.
 

The idea of the zombies pulling you in rather that pushing at you makes a lot of sense. Even better would be if you had they could latch on to you, requiring either a guard attempt (RMB) to push them off, or an attack attempt (LMB) to try to kill them in a grapple situation. Possibly adding more animations such as a neck snapping or stabbing through the eye socket or under the jaw.

 

Even further into detail sneaking should require a crouch animation, only usable by hitting LCTRL and making you move slower. You should be able to combine this with the LMB to aim at the legs giving a higher chance to knock down and possibly cripple the zombies. You should also recieve a higher accuracy when crouching and using ranged weapons.

 

Another thing that would be really amazing to see would be a running attack (which would be completely possible with depravs combat suggestions). You would charge up your attack while sprinting severely lowering your accuracy but heavily increasing your damage and knockback on melee weapons. Maybe even enabling some different kill animations such as decapitating with blades or heads bursting with blunt weapons.

[EnigmaGrey]

They don't push, though: It's basic collision. A zombie is given X space to occupy, if something occupy's it, it gets pushed out of the way. It's actually a pretty small area, if you take a look in IsoZombie (or IsoMovingCharacter, if the value is inherited and the same for all IsoGameCharacters). It can be made smaller, but the effect is to basically stack zombies on top of one another when doing so.

It shouldn't be having such a drastic effect in mulitplayer, however -- I can only assume the server finds out the zombie and the player aren't where it thought they were and overcompensates, pushing the player before or during (what I'm assuming is) their swipe/lunge.

In the normal game, a zombie rushes up to you, stops, and starts getting grabby -- there's no repulsion (unless there is a massive number, in which case you get simultaneously pushed and eaten from all sides).

[deprav]

Thanks !

The "stabbing through jaw" animation is already a thing with knives ! (and maybe screwdrivers, not sure) But the neck snapping sounds kinda overpowered, you could pretty much wander bare-handed and kill everything ;o

I'm pretty sure the crouching animation for sneaking is already planned, but I don't think the "attack the legs when crouching" mechanics will be a thing ! Plus from a technical combat pov, as zombies don't feel pain, knocking them down would have to be done by pure strenght, snapping their legs, and it's pretty hard to generate such strenght while in a crouching pose. Would be easier to do with a golf club in standing position. But that's the kind of mechanics I'm talking about when I say "the game is not built to have a realistic combat simulation."

I like the running attack idea tho !

 

 

 

Yeah I'm aware they don't "push" as it's not an intendent action but a basic way to simulate the collision, but (and correct me if I'm wrong, I'm about to talk about something I've no clue about) the fact that object occupying this X space gets pushed away must be relying on a line of code, somewhere, saying that object and this zombie can't be on the same spot.

What if that line of code is changed so that object and this zombie CAN be on the same spot, but suffers an important movement reduction speed (just like when you walk in dense forest) to the point it would almost stop both your character and the zombies.

Imo, that would give a more "realistic" collision simulation, and be much more punitive if you run into zeds, since it would give them the opportunity to grab you more easily. In its actual state, if you run straight into a zed the "repulsion" will just shift your course on the side and won't slow you down at all.

(I have to go I'm in a hurry, I think I forgot to say something!)

[Packbat]

Here's a TL;DR summary of your post if you want to copy-paste, deprav:

 

Two ways to make combat more realistic and deadly:

• As of Build 29, zombies are too weak - if you're completely idle at the controls while a zombie flails at your character, your character should be scratched or bit immediately, not 10 seconds later.
• The game should have two-button combat instead of one-button combat. Have combat stance on a toggle, then have separate attack/swing and defense/shove buttons. Force the player to be aware how close the zombies are getting instead of just spamming the LMB.

 

As for my reaction:

• From the sound of it, zombies should be more dangerous than they are, but people do a lot of stuff reflexively to protect themselves - dodging, jerking out of reach, &c. - and that should probably be automatic without player intervention. Instead of instant-scratch, I would say an untrained person should be able to dodge one ordinary zombie for at least 10 seconds, sometimes dodge two ordinary zombies for 5 seconds, and be pretty much screwed if three or more get in arms-reach ... and however many there are, it should be exhausting rather than body-damaging. And, of course, if you're trying to do something else while dodging (e.g. get a non-broken baseball bat out of your bag), it should be much worse.
• Loving the proposed two-button combat system. In keeping with my thoughts about dodging, above, I think LMB=wind-up-and-swing, RMB=push-and-shove is a good way to conceptualize it for close combat, and LMB=take-aim-and-fire, RMB=swing-or-shove would work for ranged weapons. Other thoughts:
  • If RMB actions don't impair dodging much and LMB actions tank it massively, that would create your don't-swing-wildly penalty very naturally.
  • Per the above, the kitchen knife one-hit-kill attack should be LMB, not RMB, even though it is a point-blank-range attack.
  • I would like outlines on the ground to show you the rough range of attacks with your current weapon when in combat mode - it's a lot harder to see how far away a zombie is in-game than it would be in real life.

By the way, I think they should probably introduce armor into the game - I'm sure that there are motorcyclists in Kentucky, but even if there weren't, there would be leather jackets and gloves around. They wouldn't be 100% protection, obviously, but there would be a chance of a scratch or bite turning into a reduction of Condition on the armor instead.

[MrBlackAttack]

Thanks !

The "stabbing through jaw" animation is already a thing with knives ! (and maybe screwdrivers, not sure) But the neck snapping sounds kinda overpowered, you could pretty much wander bare-handed and kill everything ;o

I'm pretty sure the crouching animation for sneaking is already planned, but I don't think the "attack the legs when crouching" mechanics will be a thing ! Plus from a technical combat pov, as zombies don't feel pain, knocking them down would have to be done by pure strenght, snapping their legs, and it's pretty hard to generate such strenght while in a crouching pose. Would be easier to do with a golf club in standing position. But that's the kind of mechanics I'm talking about when I say "the game is not built to have a realistic combat simulation."

I like the running attack idea tho !

 

 

Sorry, let me specify a little bit. Snapping necks would have to be done only with high accuracy. Meaning you couldn't just go around taking zeds out one by one with ease. However, if you did have high accuracy in unarmed (which I honestly can't believe isn't a skill branch yet) this would be much easier. Also you would be putting yourself at high risk of scratch/bite in that range.

 

Secondly, you are right about the knock down from a crouch attack. It would require a loss of strength, due to loss of full body motion. Although, I do think if you were to hit one behind the kneecap you would have a good chance to knock them down.

 

[Packbat]

Secondly, you are right about the knock down from a crouch attack. It would require a loss of strength, due to loss of full body motion. Although, I do think if you were to hit one behind the kneecap you would have a good chance to knock them down.

 

Knees are actually pretty fragile things. You could probably knock down zombies by shattering their patellas and turning them into crawlers.

 

...

[MrBlackAttack]

Knees are actually pretty fragile things. You could probably knock down zombies by shattering their patellas and turning them into crawlers.

 

...

 

Still I have to agree with deprav, that to generate enough force from a crouch attack (even to shatter a knee) would require massive arm strength, which most normal people just don't have. However, if there were an unarmed skill maybe allowing for low kicks, trips and the like, this would be completely possible.

[LeoIvanov]

I'm up for this idea as long as these things are considered in :

 

- While you're in "defense" mode with holding down the right mouse button, a single zombie would actually "continue" walking towards you and push you backwards (not stopping to play "biting" animation), while having  a low chance of scratching you, and a minimal chance of taking a bite. It all could crash down to zero if you are being grabbed by more than 1, of course, but holding 1, maximum 2 zombie mouths away shouldn't be a big deal, just grab em by their necks, or hold your wide handle of a weapon by their throats and push back.

 

- While in "defense" mode, you can ALSO press LMB to deal a slight damage to the zombie. It will be a much smaller (about 1/6th of it) damage rate than a weapon normally has, and you are probably going to be better off just pushing a zombie away, but sometimes there's moments where you CAN'T "just push them away", and you NEED that zombie who is lunging at you to be KILLED for your maneuver to succeed.  (More on this below)

 

- Weapons should completely be rid of the ability of "pushing" enemies away, making it more about "firing couple of careful shots at those who get too close and continue fleeing", than "walk back continuously while shooting, reload, push zombies back, repeat until run outta ammo/zombies to kill". Once you're stuck in the "defense" mode with your weapon, while a zombie is pushing you back, you'll need to press "LMB" to shoot a zombie's head with a high critical chance, or continue pressing LMB to "hit" it with a handle, in case you ran out of ammo. That way you can put it down, although it'll greatly damage your weapon's durability, forcing you to count your rounds carefully and make sure not to get caught off guard. Releasing RMB while in defense mode will immediately skip to zombie's "biting" animation, in that moment you'll also be "pulled in" or "held from moving" like you normally are during those encounters. The problem with this is that you'd have too small of a time to get away without getting ANY damage.

 

- Small tweaks regarding the pushing. If you push a zombie into a zombie, both zombies have their chance of: 1) falling down 2) getting shoved back 3) getting slowed down. It all depends on the momentum of an impact of that particular zombie. That way - if you forcefully pushed a zombie back (normally it would fall down if nobody was behind), it will send the second zombie behind him stumbling back and falling (if nobody is there), or pushing a third zombie away stumbling. A third zombie will have an even smaller momentum, so the only thing he could do with the fourth zombie is slightly slow him down. (More on this "momentum" idea below)

 

- Each zombie has momentum behind them, depending on their walking speed. A standing zombie has minimal momentum (zero), so if you push another zombie into it, they are both likely to fall. However, a zombie walking towards you has a bigger momentum because it's moving forward, so pushing a zombie into him will have very mixed, very different type of results with each try. If a zombie's momentum is greater than the force of opposite momentum, then the zombie that was originally shoved away will produce zero results on impact, and you'll likely end up with two zombies chasing you simultaneously. However, if a zombie's momentum is lower than the momentum of  the opposing, shoved zombie, then the chance of falling/slowing down/getting pushed away are calculated on the spot.

 

tl;dr - ADD PHYSICS BEHIND "DEFENSE" MECHANIC OF THIS SUGGESTION!!

[Ohbal]

I also think zombies should be more of an actual object, more solid to speak- I should NOT be able to run through a crowd of them and only being slowed down briefly. I should be bumping into them, getting moshed and then violently mobbed by them, zombies should not be easy to run through if they are clumped together and I think a collision system would fix a lot of the problems of the game being too easy off the bat.

 

This is something related to the discussion about OFTLGBKYBYGT (geez what an abbreviation!). 

 

I kind of disagree with this... 

 

As far as the classic zombie lore goes, zombies are both easy to dodge and easy to out run. 

 

The Zombie menace comes from two things:

 

1. Large numbers

 

2. Human Error (over confidence)

 

3. Element of Surprise

 

On an open road with good visibility, a skilled survivor shouldn't have any problems if all he wants is to keep moving. The survival problems comes once you stop, and you have a massive horde following you. 

 

Romero's movies, Resident Evil, WWZ, TWD, Dead Rising... and most of the iterations with zombies that do not imply runners are working by these rules. 

 

The characters of those movies / games do not face particular troubles on the Zombie-Dodging art. Its one of the things that makes you feel like you are in control, that you are better than those stupid and slow non-dead... and is precisely that sense of over-confidence which gets most of the people killed on those movies / books / games. 

[EvaN]

I feel more like a threat for zombies than them being a threat for me.

 

Agreed. In the current build, proper zombies are only dangerous when badly outnumbered and cornered, which pretty much never happens if you are just a bit careful.

 

i don't know how to make proper zombies more of a threat, but your suggestion would be a good start.

 

In the meantime, for increased challenge, I play with Sprinters. As much as I do not like sprinting zombies, it indeed makes them dangerous :

Unseen zombie jumping on you ? Almost garanteed scratch/bite.

1v1 ? Easy, just try not to f*ck up your timing.

1v2 ? Hard but manageable. Low chances to walk out untouched.

1v3+ ? Run like a motherlover (if you can... losing them can be quite tricky).