Extra weapons:
Type baabaa at the weapons option screen. Exploding sheep, the banana bomb, and full motion with the ninja rope will be available during game play. Type aabaab at the weapons option screen to disable cheat mode.
Unlimited Sheep:
Type bobjob at the weapons options screen.
Rapid fire missiles:
Type aabaab while shooting a mini-gun.
Extra turn:
Type aabaab while firing a banana bomb.
Unlimited bazooka missiles:
Select a target with the Uzi, then hold [Shift] + [F1] and press [Space].
The funniest levels are under these codes:
70345
223981979
7373888390
4802043
And then a couple of level codes:
Level 02 -- OHSOEASY
Level 03 -- UNCHAINS
Level 04 -- BJORNPOP
Level 05 -- DODGEMAX
Level 06 -- STARTURN
Level 07 -- HEYGEOFF
Level 08 -- REZDOGGY
Level 09 -- HIGHKICK
Level 10 -- LONG AGO
Level 11 -- HEY JOHN
Level 12 -- SATANICS
Level 13 -- NEARDEAD
Level 14 -- SCUMBAGZ
Level 15 -- GOOD BYE
Level 16 -- TRUTHOUT
Level 17 -- 17THKIND
Level 18 -- GOGOGOGO
Level 19 -- PIGSPACE
Level 20 -- TRUMPTON
Level 21 -- PARANOID
Level 22 -- MIXTURES
Level 23 -- VERY MAD
Level 24 -- INSANITY
Level 25 -- GREATGIG