Hmmm.. it appears there are only three levels in this special pack. According to video (since I don't own the game): SMB 1-1, SMB3 1-1, and Mario Bros stage
Not that I'm complaining too much, I hope.. I just kinda thought it would be moreso "select handfulls of levels from *insert game here*" (except Mario Bros. There are only so many ways to make that stage a new stage..)