Use ResEdit to open the "BOOM Levels" file. Open the "levls" resource to access any of the 80 levels. Select a level to edit and change the time and the background image. Enter the following characters to change that feature.

X: Player one starting position
Y: Player two starting position
2: Destructible blocks
0: Space
1: Indesctructible blocks
3: Coins
A, B, C: Various enemies