Some issues I encountered while playing:
1)Controls are too jerky: when you fall between rows of sawblades it's too hard to control, and you run into them and die. Also, it's really hard to jump onto a platform above you.
2)Controls are explained properly, for example I didn't know that you could double jump, until I realized that the level would be unbeatable without it.
3)Same with the hazards, you could've added text to indicate that the grey round things are sawblades, that instakill you.
4)There is no reason for wooden logs to have such inertia and to be able to rotate.
5)There is also no reason to use mouse to control anything, cause you don't use the pointer at all, you could've attached attack to a keyboard key.
Other than that I think with some polish you can make quite a decent and enjoyable game.
Good luck!