Message from Krusty the Clown:
Some pesky rats have infested my lovely fun house up in the Springfield hills
and I need your help to get rid of them!
These rats are real dumb, they just walk around climbing over anything that
isn't bigger than they are. If they reach a wall or barrier that is higher
than them, they'll just turn around and go the other way...
Use the blocks and items that you find lying around to move the rats around
the level to those wacky traps where Bart, Homer and my faithful helpers
Sideshow Mel and Corporal Punishment are ready to help us get rid of those
--from the Genesis Krusty's Super Fun House game intro
Well, that pretty much sums it up. You play as Krusty, run and jump around the different levels and figure out how to get the rats into the trap. Watch out for enemies, and make sure to get back to the entrance of each room before you get creamed yourself.