Gorf is pretty fun, especially if you only have 1 quarter left and want to a few different games, but Satan's Hollow is better.
None of the Gorf levels are as good or fun or strategic as deciding when to grab that bridge piece and when to place it. I also like that it's a lot of knowing when not to shoot. You have to pay attention to more factors, including bridge status, number of monsters left on the screen and what's board is coming next.
The shield timer is great, too.