Earthworm Kim
Collect 1000 marbles and successfully complete the game with a Smart Superhero rank to unlock Earthworm Kim. The difficulty of the game will increase when played as Earthworm Kim.
Go to the Fear part of the Brain and enter the door on the right of the Sacred Cow Of Contemplation. In this room is the way to the levels Poultryguyst and Poulrtyguyst 2. You should see a door blocked by a metal gate. If you have all 1000 marbles and have beaten Earthworm Kim, the gate will open. Walk through it and the game will automatically reset. When you start the game again, Earthworm Jim usually hops around playing the accordion -- this time Kim will be the playing it and will soon be smashed by a cow. Press any button to get to the file select screen. You should now have a fourth file as Earthworm Kim.