Earthworm Jim
  
Gameboy Advance


  


Level Select:


  Press Start to pause game play, then press Right, R, B, A, L, L, A, 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 R, L, R, L, A, R. 


  


  Level 5 Level:


  Press Start to pause game play, then press R, L, A, B, B, 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. 
  
Thanks to Revolution reader gamer2101!