MegaCheat:

 Press at the same time [W][A][X] and you get everything.

Cheat:

 Start the game with  c7 president.  Now choose PRESIDENT from
 the difficulty menu.

 Start the game with c7 level1diagnostic. Now you can activate the
 cheat mode by pressing [Crtl] [leShift] and [TAB] together. You
 now have with ...

 [Backspace]-[W] - Level warp
 [Backspace]-[G] - God mode on/off
 [Backspace]-[N] - Walk through walls
 [Backspace]-[R] - ;-)
 [Backspace]-[I] - Points
 [Backspace]-[S] - Freeze game

 You can also try [Backspace]-[P], -[F], -[C] and -[M]. Check them
 out yourself.

HexCheat:

 If you are into manipulating files, you can get some of the effects
 above also with hex editing the file corr7.exe. You can get
 invulnerability and unlimited bullets if you

 search for         83 2E BA 48 02 83 3E BA
 and change it to   90 90 90 90 90 83 3E BA        and

 search for         FF 0E BC 48 9A D1 0A
 and change it to   90 90 90 90 9A D1 0A           and

 search for         29 36 BA 48 56 9A 37
 and change it to   90 90 90 90 56 9A 37