What a unique idea with the loop! Love that you made the little guy yourself :)
We got quite stuck on the loop where you have to grab the thing that looks like a grappling hook. It's awfully easy to overshoot where you jump/land once you get a speed upgrade. Also the character seems to only be able to jump two blocks high reliably when no other direction is being pressed (aka pressing both jump and left/right means the character doesn't make the jump) which is a bit frustrating because being able to press both and still reliably make the jump would probably save some time.
The game would also probably benefit from some sound (as you already know) and maybe a bit of a narrative? Giving the character a goal would make the repetetiveness of just grabbing upgrades more rewarding.
Overall great job though and compliments on the concept and doing it all yourself!! :)