When I reached the crystal, I actually uttered out loud, “please don’t be the end!”. This is awesome! Great use of color and contrast, nice subtle training that ramps up just right and lets the player experiment. And the tone overall is just spot-on.
A couple things if you’re going to keep working on it – and you totally should:
- Don’t require a mouse click for the arrow, let the keyboard do it too.
- Also gamepad input would be great.
- Try a bit of coyote time when stepping off a platform.
- Try parallax scrolling for the background, I bet that would look really cool.
If this was much longer, with extra gimmicks, maybe some monsters to kill? Man, I would play the heck out of it :)