Road Rash

Cheat mode:
Type xyzzy during game play to enable cheat mode. Then, enter one of the following codes during game play to activate the corresponding cheat function.

Effect - Code 
Get club - k'thunk! 
Get chain - thwack! 
Refill nitros - spoon! 
No more cops - bribe 
Eliminate police - yes,occifer 
Killing mode - overkill 
Disable cheats - plugh 

Alternate Sierra Nevada image:
Select thrash mode, highlight Sierra Nevada at the bulletin board, then press A. 

Restroom bonus:
Press A a few times in the restroom in thrash mode to see a man vomiting.