Press T, then activate the following cheats by entering the corresponding codes:
CHEAT FUNCTION - CHEAT CODE God mode - mpkfa, cap in my ass, I wanna be like Kevin Temporary God mode - voorhees Disable God mode - no cap in my ass All weapons, ammo - lara croft or hongkong All weapons and items - idaho All items - montana Allow two of same weapon - bunz All items - satchel 100 % health - clarice 200% health - spork 200% health, on fire - krueger 200% health, diving suit - cousteau 200% armor - griswold Level skip - calgon, mario, or luigi Level select, cheats disabled - spielberg Temporary blindness - sterno Invisibility - onering Display framerate - rate Suicide - edmark or kevorkian Suicide by fire - mcgee Drunk mode - jojo Higher jumps - funky shoes All keys - keymaster No weapons, 1% health, drunk - fork broussard Toggle clipping mode - eva galli Full map - goonies
After you the Moon Key door in the carnival level, Don't dive down the lake under the destroyed pier. Instead, jump across to the other side using the remaining wooden pillars as platforms. Once on the final pillar, destroy the crack in the wall and dive into the water behind it. Swim to the end, and you will find yourself in a small chamber with a Life Seed, Super Armor, and a block with three Skull pictures on it. When you use each picture, it will change and cycle through the graphics on each key in the game. Change the pictures on the block to Dagger, Eye, Moon to make the block retract into the ground and display the message "You're going to the secret level".
On episode 1: level 6, enter the JOJO room. Walk to the front of the snake pit, then press SPACE on the warning sign on the left. Immediately get behind the snake pit to enter a secret area that features Duke Nukem hanging from the ceiling.