Earthworm Jim Cheats - GBA

Level select
Press [Start] to pause game play, then press [Right], [R], [B], [A], [L]x2, [A], [R].

Alternately, press [Start] to pause game play, then press [R], [L], [A], [B]x2, [L], [R].

Buttville level
Press [Start] to pause game play, then press [L], [A], [Up], [R], [A], [R], [A], [Select].

Down The Tubes level
Press [Start] to pause game play, then press [Up], [L], [Down], [A], [R], [A].

For Pete's Sake level
Press [Start] to pause game play, then press [Right], [Left], [R], [L], [A], [R].

Level 5 level
Press [Start] to pause game play, then press [R], [L], [A], [B]x2, [A], [L], [R].

Snot A Problem level
Press [Start] to pause game play, then press [R], [Up], [Select], [L], [R], [Left].

What The Heck level
Press [Start] to pause game play, then press [Select], [R], [B], [Down], [L], [B].

Portal to Garbage Can Man
In level 1 is a field of tires after the cow launching. Jump on one of the three platforms to the left -- there will be two ziplines to the left. The first will go to the left and the second is below the first and goes to the right. As soon as you get on the second zipline, jump off to the left to land on a chain. Go left on the chain until you get to land. There will be four ziplines above you. On the topmost zipline, jump off to the left onto some land. There will be two dogs you have to destroy. Keep going left until you drop onto a lower platform. There will some bullets there. Drop down again to find a toilet. Jump on the toilet and you will transported below the battlefield of the Garbage Can Man. There will be more bullets and an extra life located there.

Snot A Problem: Easy level
Hold [R] until the rope breaks.