I enjoyed playing through this quite a bit. :) I think the game plays well for a Mario-like.
The level I had the hardest time with was 3-1; I don't know, maybe another cheese power-up or two would help with the two hammer bro encounters. And there were a couple points in boss stages where ceiling blocks got in the way of jumps, making for frustration. And maybe late stages had a bit much emphasis on long jumps that require the run button. But these were my only sticking points; all in all the game had the right amount of challenge and a lot of fun.