I think that killing floor is awesome for starters. However I feel as if it is missing a lot of material.
Guns: for one the selection is very small so adding some more weapons would be great. Like an actual sniper rifle, different kinds of grenades, perhaps a mini gun. Those are just off the top of my head. Or give us the ability to upgrade the weapons
Class changes:
Medic: more medic specific guns, shock paddles to revive dead allies (like in left 4 dead 2), medkit that doesn't need reloading or shorter reload down by at least 75%, and perhaps a chance of revival ability (like if you die you could answer a quick question or something if you get it right you come back before the end of the wave limited to one time only)
Commando: bigger guns should be available, knife and any other melee weapon should do more damage, faster reloading, and perhaps an execution ability
Sniper: more weapons with scopes should be available, should run faster and/or be able to avoid clot grappling, and perhaps some sort of stealth ability.
demolition: should start with full grenades and/or 2 mines, perhaps the ability of a sticky grenade or chain explosives or minor explosive rounds to demolition specific guns.
Support: should carry extra ammo, should be able to give others ammo, should start with a a hand cannon instead of a 9mm, perhaps a sentry gun ability.
Berserker: should be able to have at least 25% more maximum health or start with armor, start off with an axe instead of a knife, perhaps the rage ability making every slice a 1 hit kill for a limited duration probably use either damage taken or by number of kills.
Fire bug: should have more weapons if possible or weapons with incendiary rounds, should have failsafe explosion when dead, the abiliy of immolate (causing the ground to burn for a duration)
In turn with leveling up the classes to get their perks there should be a separate leveling system that can allow for player to have earned perks by leveling: dexterity (speed), (strength ( melee damage and carrying weight), endurance (health) and a single point to go towards weapon specialization like if you like the cross bow you can make your character slightly better with it.
Guns: for one the selection is very small so adding some more weapons would be great. Like an actual sniper rifle, different kinds of grenades, perhaps a mini gun. Those are just off the top of my head. Or give us the ability to upgrade the weapons
Class changes:
Medic: more medic specific guns, shock paddles to revive dead allies (like in left 4 dead 2), medkit that doesn't need reloading or shorter reload down by at least 75%, and perhaps a chance of revival ability (like if you die you could answer a quick question or something if you get it right you come back before the end of the wave limited to one time only)
Commando: bigger guns should be available, knife and any other melee weapon should do more damage, faster reloading, and perhaps an execution ability
Sniper: more weapons with scopes should be available, should run faster and/or be able to avoid clot grappling, and perhaps some sort of stealth ability.
demolition: should start with full grenades and/or 2 mines, perhaps the ability of a sticky grenade or chain explosives or minor explosive rounds to demolition specific guns.
Support: should carry extra ammo, should be able to give others ammo, should start with a a hand cannon instead of a 9mm, perhaps a sentry gun ability.
Berserker: should be able to have at least 25% more maximum health or start with armor, start off with an axe instead of a knife, perhaps the rage ability making every slice a 1 hit kill for a limited duration probably use either damage taken or by number of kills.
Fire bug: should have more weapons if possible or weapons with incendiary rounds, should have failsafe explosion when dead, the abiliy of immolate (causing the ground to burn for a duration)
In turn with leveling up the classes to get their perks there should be a separate leveling system that can allow for player to have earned perks by leveling: dexterity (speed), (strength ( melee damage and carrying weight), endurance (health) and a single point to go towards weapon specialization like if you like the cross bow you can make your character slightly better with it.