Probably my favourite of the 2D Mario games except for SMB3. It contains the most interesting mechanics, and is without a doubt the hardest. It is so relentless that I had to use save states to not spend 300+ hours on completing this game, because you get thrown back to the beginning if you get a game over and waste all your retries. The music in this game is damn good, especially the main overworld theme and the final boss theme. The level design is overall pretty solid and completing levels is very satisfying. A pretty good game.