The engine sucks
I had some expectations for a game like this.
But........
You do a less than satisfactory job in the game.
The collision detection is horrible, whether it's death by a hawk a couple pixels away or trying to a "vertical bypass jump" and hitting an invisible block. Or slipping through a 'solid' block from the side.
Aside from engine problems problems, there was the simple fact that YOU COULD NOT ACTUALLY CONTROL YOUR JUMPS! There was only one jump height! And it was highly annoying to be stuck with that. A good platformer gives you the ability to make jumps of different heights! Look at Super Mario, Megaman, Metroid! You could make tiny jumps AND still make a ridiculously big one.
Jumping aside, a handful of level designs were quite evil. Level 25 is where I ended up stuck. Though I do freely admit that I am not the best platformer, it had some incredibly irritating timing, along with a few others.
Decent job, but you should be able to make a less glitchy engine for it. Really the only big problem is the engine. Improve that and the game would be fine.