needs sound and some kind of reason to get points, like maybe a new hat or something.
also, you could make the backgrounds change every 10k points or so just to make it more interating.
could also use a start button

add arrow keys

If someone wants to play that, every button other than arrow keys is jump button

It's a game. That is for sure.

Firstly, it could do with some instructions (controls?). I'm guessing this is just a one button, platform jumper. Though the yellow thing that darts off away from you at the start of the game confuses me. Am I supposed to shoot it? Catch it?

You really need to add a home page which could link to an instructions page maybe credits (makes it look a little more professional) and a start button. Then think about more advanced stuff like collectables for points as well as earning it through distance.

Needs sound