Instructions
Start the game and choose "Factory Zone 3," then "Entry Point 4" from the levels menu. If you haven't reached this level, you'll need to play through until you have it unlocked.
Select "Rocko" as the first character in your party. The choice for the second character to include in your party is up to your own personal preference since they all work well with Rocko. Danny Phantom does especially well in this level for fighting the flying monsters at the end.
Start the level and you'll find yourself on a side-scrolling platform with a spaceship following along behind you. Run fast enough to stay ahead of the spaceship and double jump over obstacles in your path.
Continue through the level until you see a green image of Rocko. Jump on it and you'll be transported to the next area. Continue across the platforms to a pipe at the end of the level and enter it. This takes you to the last battle.
Hit the various enemies in the last level to stun them and continue hitting them until they've all been destroyed. Look for a square on the floor with a symbol on it. Stand on top and do a slam jump by pressing "A" to jump and pressing the "Down" arrow while in the air.
Run up the stairs that appear after you slam jump the square in the floor. Slam jump the container with GIR inside it to add him to your collection.