Pause gameplay and press L, A, Up, R, A, R, A, Select.
Skip to Down the Tubes Level
Pause gameplay and press Up, L, Down, A, R, A.
Skip to For Pete's Sake Level
Pause gameplay and press R, L, R, L, A, R.
Skip to Level 5
Pause gameplay and press R, L, A, B, B, A, L, R.
Skip to Snot a Problem Level
Pause gameplay and press R, Up, Select, L, R, Left.
Skip to What the Heck Level
Pause gameplay and press Select, R, B, Down, L, B.
Snot A Problem: Easy level
Hold R until the rope breaks.
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.
Level select
Press Start to pause game play, then press Right, R, B, A, L(2), A, R. Alternately, press Start to pause game play, then press R, L, A, B(2), L, R.