Super Mario 63 is a very well done flash game, the game is huge and there are very few problems. The game will occasionally have a slowdown, which on seldom occasions will make the game unplayable, but just stop playing for a few moments and it will be fine again. The levels are well done and the enemies are fun to stomp on, the game might be a bit too easy, but it has tons of replayability. This game is huge, lots of fun and will easily take you 2+ hours to beat the whole game. I would rate this game higher than my Gameboy sidescroller because of the levels are extremely varied and generally more fun to play. I highly recommend you play this awesome flash game, save your money buying that new Mario game and just play this!
The Boo's are extremely frustrating and annoying, some rooms had 5 or more and this became extremely difficult because
1) cannot be killed
2) they can cause damage even when hiding.
I find that they respawn a little too quickly, moving slightly away from the defeated enemies will instantly respawn them, which gets annoying if there are a large amount of them.
Use [ARROWS] to move and JUMP around