Perfect! (yes it is!)
The game is EXTREMELY challenging (lv 19 is not impossible, and, if you are fast, you can press R and restart the level. It is just a bit more manual to respawn in this level), i loved everything, the song (for some reason everyone thought the song was ridiculous, but in my opinion, i fits with the game and it is pretty nice!), the simple controls (the character is very fast, witch makes the game even more challenging), and even the simple story (simple, but brilliant, the character has no name, you are playing the whole game in somewhere you do not even know where it is, maybe a dream/fantasy world, and you get helped by an anonimous voice that does not help you fisicaly, it only teaches you the basics. And the endings! I loved the endings, two beautiful messages!)!
Concluding my review: i give a nice ten'o ten for this marvelous game.