The sprite work on the game is good and not choppy, but it is pretty familiar and never really touches really new ground except for boss fights. Worlds are unique atmospheric, but are formulaic for a Mario-themed game. It looks professional though due to cool little touches.
Tunes in levels are catchy, but recycled sometimes. Mario sound effects are utilized in the same fashion as usual here.
This is the category that got the game on the website. The gameplay on this Mario-themed game is some of the best I've played in a 2D Mario title since Super Mario World. It's very much spiritually an entry into the World series, and it's insanely hard, fun, and lengthy.