A short, easy hack with simple platforming. It's incredibly straightforward. The final level has a wide-open area where you swim with star power and I feel like water levels need a little more strictness of direction since most things are easily avoidable.
There is a graphical bug with the kill frame of the Koopas. Also, the "intro" level's opening is kind of illegal as far as submission standards go: start swimming right away or you'll drown in the first second of entering the level. I find it really weird that munchers were changed into dark moons, but if the hack were ever updated, maybe we'd see these things floating - I don't know.
Dire Dire Docks will kill the hack in accurate emulators. The channels of the port that plays in the first few levels sound really, really desynced.