Here is a list of the main console commands:

NEW start new game
RESTART restart current level
QUIT quit to dos
CHOJIN immortal code
AMMO restore ammo for all weapons
INVISIBLE gives 2 minutes of invisibility
ARMOR gives 200% of armour
FULLMAP allows you to see the full map of the current level.
KILL kill all monsters on the level
REANIMATE reanimate all monsters
RESPAWN <#time> set the monsters respawn time (#time=0 means no respawn).
SHADOWS set the upper limit of shadows casting by 3-D object.
GO <#level> warp to specified level.
WEAPON receive all weapons with ammo