Super Mario and the Cursed Castles

Super Mario and the Cursed Castles is a major ROM hack created by Foxen, having 121 Stars (as of v1.01) to collect spread over 15 courses and a few extra levels. It is notable for two reasons: The lack of any true "secret" levels (all Stars are located in levels that are easy to find), and the sheer size of the game's levels.