its hard to say what is needed to be added in this game but all I can suggest is that we have coins and cash etc and with that we will be able to buy weapons and even other classes (classes must be very expensive)
there should be sprint bar where it shows when you get tired and also add ammo you cant just have infinit ammo thats not fun and if you can could you change the skin of the bazooka in the red team I dont even know whats that weapon anymore lol
there should be co-op gameplay with several modes like survival where either zombies like things or robots attacking you and ur teammate .Its always fun to play with a player better than AI ^^
Razordis are you kiding me? zombies require alot of skill all you need is alot of patience and speed no need to make it harder and harder and harder
also I suggest you add a ranged weapon to zombies like acid spit:the spit should have the max damage 20
it takes 15 sec to recharge the spit
the speed should be average
also can you make the vision of the zombies better I cant even see better than the suvivors
there should be money a credits like for example: with every win we get :coins and every time we lvl up we get OGAT credits
and with those credits we buy skins and weapons and classes