Dark Shark, you're "not taking any chances?" Do you not like Mario games or something? If so, why are you on this board? Color me baffled.
Anyhow, this game, other than a couple of minor details, is a gift from God. It's (really really close to) everything I've ever wanted from a Mario sidescroller. The level design, with it's plethora of secrets and cool gameplay quirks, is a joy to behold. Here's hoping we get a sequel (Newer Super Mario Bros.?) sometime soon.