Thx for the replies everyone (since I'm a first-poster)! Of course buying extra copies is always a possibilty and I might even do that for one or the other friend of mine, but I was thinking about ways that espacially encourage people to support PZ who already own the game. I didn't thought about mods and their relation to that kind of payment system, therefore, good point. I agree that modding plays a vital part in the success of games that shouldn't be underestimated. Not necessarily. Instead of keeping content back from one part of the player base (which I dislike as well) I rather thought about possibilities to encourage further financial commitment that isn't necessarily connected to extra content. (PS: thx, next time I use it ) I guess I got off the wrong foot. Let me explain: I'm not promoting P2W (I really really really hate P2W)! PZ is not a F2P (free-to-play) game, therefore, micro-transactions that unlock (even aesthetic) content would be ridicoulus and unfair. I don't want that to happen. Instead PZ is a P2P (pay-to-play) game (like most games ). But since it's an indie game it can benefit greatly from further funding. If I buy extra copies for some friends that would mean, that they won't buy a copy themselves - maybe they would've never bought the game in the first place, maybe they would've. Point is, that there might be better ways to contribute to PZ. Sure, I can write a mail and transfer another 10 bucks to the project - I don't need anything in return - but that's not the point. I totally agree, that the contribution of modders is fantastic and has to be acknowledged (like TIS is doing on their website) - but I'm not a modder, are you? Here is an example (not a very fancy one, I know ) that illustrates what I was thinking: ... let's say you pay 10$: your name gets randomly assigned to one zombie per map loaded (f.e. "your name" appearing in the inventory menue when looting a corpse of that exact zombie) ... let's say you pay 25$: a street in muldraugh is named after you (f.e. appearing in small letters in the bottom right corner while walking over that exact street) ... let's say you pay 50$: you get your name in the "contributers list" in the credits (f.e. appearing after death)