I agree with the comments made about the controls being a pain. Maybe accelerate could be space while fart could be mapped to F so that we don't have to move the mouse between the two.
As a way to reset recoil and ammo for a gun (Not those with one in the clip) you can press "z" then "x" really fast to switch guns and back the one you were using. Switching guns resets the ammo count for that gun and the recoil. Better than waiting for the reload to finish. For maximum efficiency, switch when there's 1 or 2 ammo left.
Just a suggestion - After the ive single player missions you should be able to do what you do in multiplayer, except by yourself, so an option which lets you to make your own scenario and go solo.
I wonder if we could possibly see a stats page with stuff such as: kills, favourite weapon, kills/weapon, kills/class, games played, accuracy, number of deaths, headshots, times headshotted, etc.
I reckon there should also be a 'custom game' option after you finish the last boss where you pick a map, number of opposing teams, and how many people per team, what armour they have and the AI difficulty. That in addition to badges and multiplayer.
See, when I click 'Info' in the upgrades menu, I want to see what that upgrade does, not how many Kreds it costs, and what other special things I can get if I paid Kreds.
I love the game. Simply great. A good end-level interface as well, which a replay, next level, level select and upgrades. It would be awesome if there was a 'stats' page, with enemies killed, types of enemies killed, shots fired from each weapon, how many 'superpowers' from each weapon used, favourite weapon, etc.
I think the most annoying thing about this game is when you hit something, and the "The x is damaged" thing comes up, blocking the top left view of the screen.
Might be a bug, not sure. iFinished building the car, just as Wave 33 started, then I decided to keep on killing zombies, and at one point I died. When I clicked "Retry", all the car parts were visibly scattered across the forest (Even though when I started to repair the car, it was at 8x%. Basically, the sprites of the car parts re-appeared.