This is a nice little experiment, it does what is meant to, but that doesn't exactly mean it is a great game.
After trying all the modes, I found the first one to be the most annoying as the camera follows the feet of the player, so you are not able to see the blocks that have appeared since you have jumped, which could lead to getting stuck and not being able to time the jumps right. The rest of the game modes were rather easy, a bit fun and simple. They didn't bother me all that too much, except when I jumped on the boss when you were able to damage him and he instantly turned back to damage mode and I lost a life.
Also, to Pakken11. The impossible game used these songs, but that does not mean that it created them or has the right to do everything with them.
Many games used these exact songs way before the impossible game if I remember correctly, so no, they should not have to include that in the description.