If you haven't been over to
Defunct Games in a while it's worth heading over there now as Cyril has been posting some of the top bonus stages of all time as part of his 31 Bonus Levels of Christmas series. So far he's covered
Super Meat Boy,
Devil's Crush,
Sonic the Hedgehog,
Mortal Kombat, and
Galaga.
It's a really good look at one of those things the industry doesn't really do as much of any more and there's no one better to talk about the history of games than Cyril.