Apocalypse

Level skip
While playing the game, hold down SHIFT and type in "ELIZA" to
jump to the next level.

Cheats:
On the level/player selection screen, move the mouse to the crystal
at the top of the Apocalypse logo. Imagine the mouse buttons are
numbered like this:

SELECT 1
MENU - 2
ADJUST 4

Holding down various combinations of buttons activates a different
numbered cheat mode, according to the sum of the held down buttons.
The cheat mode levels run from 1 to 7, although 5 to 7 are the same.
As the cheat level gets higher so the better the cheats become. On all
cheat levels you can select any planet to start at. At cheat levels 3
and higher the shield charge increases, at levels 3 and higher you
have rapid fire, and the gun temperature coole ricky to select any
particular level, so a way to get cheat level 5 (the best) is to
press Z to continue instead of SPACE when you insert the levels
disc.