God Mode:
To play through this tough game and take no damage, press the "~" key to bring up the console, and then type:
GodDebugToggle()

Slow Motion mode:
As Max, hold the Fire button and press the Equip Up button four times.

Level Codes:
While playing you can press the Tilde (~) button and enter one of the following codes to open the level you want:

Level 1
mdkNewGame(1,12)

Level 2
mdkNewGame(2,12)

Level 3
mdkNewGame(3,12)

Level 4
mdkNewGame(4,12)

Level 5
mdkNewGame(5,11)

Level 6
mdkNewGame(6,8)

Level 7
mdkNewGame(7,11)

Level 8
mdkNewGame(8,8)

Level 9
mdkNewGame(9,13)

Level 10
mdkNewGame(10,7)

Level 11
mdkNewGame(11,1)

Level 12
mdkNewGame(12,1)