aright some ideas i just want to throw out there
for the levels here's some basic ideas
1. a desert level sandstorms would happen randomly with low viability zombie coyotes,
2. a level that takes place in a ruined skyscraper maybe have all the players start off in separate floors, include grappling hooks, elevator shaft where you can climb up or down.
3. on board a huge ship in the middle of a storm
weapon ideas
1.a gun that shoots out a net maybe add electricity or where the net constricts on the zombies slicing them up
2. a 6 barreled grenade launcher different types of grenades similar to resident evil 5 called the devastator
3. gun that shoots out spikes sticks them to walls
4. more melee weapons machete, spear,chainsaw but you have to buy gas for it
perks
1.mimicry lets you pose as a zombie for 20 seconds and then it charges, so if you get cornered it lets you escape
2.ammoclip doubles your reserve ammo for all guns
3.adrenaline lets you kinda slow down time
other ideas
1.equipment machine lets you buy scopes attachments just more things
2.pack a punch twice
3.upgrade the perks
4.a drop called frenzy all the zombies start killing each other
5. each character has there own unique moves or special
6.lets you share points ammo weapons