Open  Game.ini  file  with  notepad,  search  for  these two line
QuickBoot=0  and  ShowVersion=0.  Change  both  of  the 0 to 1 for the
discribed  functions  below. Also make sure EnableDebugMenu=1 is there
(the game should generate it by itselves, but check to be sure).

QuickBoot=1 - Will give you access to a build in level selector

ShowVersion=1 - Will give you access to a build in debug menu, with the
                   following cheat options:

Collect All Lemons
Soak test
Unlock all levels
Jump to End of Level
Invulnerability