This was a fun little game. The coins were sometimes a helpful guide, and sometimes an extra challenge. I did collect all of them on the second level though! The sfx are good feedback, though balanced a bit too low.
There are some UI issues at play. The “next level” button on level three was, I think broken? I ended up playing through that one three times, thinking that the first two I may have locked the next level by dying at the same moment as my finishing, but the final time I was very thoroughly on-screen and it still sent me back to the start of that level. Level 4 was never reachable. On the topic of buttons: avoid having a Quit button that closes the game. Just, in general, it’s bad to have such a button at all, but it’s especially heinous in a web build because it doesn’t actually close the game or defullscreen it or anything, it just stops responding to events, basically killing the tab.
Gameplay-wise, everything felt good and responsive. Simple, but that meant you could really focus on making each part good.