just finished the game, and I have to say that this is truly inspirational... the end flag gave a tear to my eye, I don't think that there will be another masterpiece like this for a while.
The mechanics are so refined, the hitboxes rewarding, the difficulty the perfect mix of difficult and still fun to play. With every new gimmick, (my favorite being the skateboard), the challenges became more complex, leading there to be so much for speed runners to use.
Overall, 27/27, would play again!