Final Code  -  "mst3K" : The final code to the last boss of the entire game.

God mode:-  Hold [Command] + [Shift] and type godim.

All weapons:-  Hold [Command] + [Shift] and type 0wpn.

All keys:-  Hold [Command] + [Shift] and type 99sesame.

Level select:- 
Hold [Command] + [Shift] when selecting a new game. Levels 1 through 28 are single player, levels 29 through 40 are multi-player.

Level Passwords

5 NODE
10 PACKET
14 MYCIN
18 EURISKO
23 DEEPBLUE
26 HACKER
29 WIRED