Left 4k Dead was made by Markus Persson,
for the 2009 Java 4k Competition.
The entire game is less than 4kb.
The game is inspired by Left 4 Dead by Valve Software.
How to play:
Use WASD to move. Move the mouse to look around. Press the left mouse button to fire. To reload, press R. Yellow powerups restore clips. Red powerups restore health. Beating a level means the game gets harder, but you get more points for each zombie.