1.- I suggest putting an option in sandbox settings for runner zombies to walk and then run if you get a bit closer to them, they walk towards you if they spot you and if you let them get a bit closer or if you get closer to them, they now run towards you
2.- Scenarios that requires or gives you an especific amount of points depending on the difficulty
3.- Chances for lockers to be locked (since you can get guns easily with just a key, for example: the police stations)
4.- A new magazine that gives you the ability to open locked doors with a crowbar and the ability to lockpick lockers
