First I'd like to mention that this review is based off of a casual single-player experience. I didn't collect all the Star Coins, but I plan to whenever I come back to this game. The level design is much better than the other two Mario games I recently played (Super Mario Bros. and The Lost Levels), though there are a few levels or gimmicks I didn't like, such as any gimmick from World 2 or the wall climbing in World 6. The difficulty is just fine, simple when you want to run through levels but harder when you want to collect the Star Coins. This isn't a complaint that would dock any points, but the world design is really boring since it follows the generic pattern of having a desert, ice world, water world, etc. I understand that this game is really old, but I wish the Mushroom Kingdom just had more unique scenery especially since the other 2D Mario games do the same thing. I would like to see a NSMB game with a world design like in the 3D games like Sunshine or Galaxy. Overall, very simple yet fun game that I definitely see myself returning to.