This is a fun little title! It's definitely a little undercooked but it doesn't treat itself as anything bigger than it is.
The jumping physics did feel a little weird, I would sometimes just fall straight into a pit after jumping a few times, though I'm not sure if perhaps there's some sort of mechanic preventing you from jumping for too long without landing on a platform?
My biggest criticism is the UI. The menus appear to only be activated by clicking (I could be mistaken for reasons I'll elaborate on in a sec), and the game stopping dead in its tracks to ask you to type in your name for the high score was pretty irritating. The gameplay loop on this is super fast and short, and when I die I want to get right back into it, so the entry window appearing halts all momentum. If you click cancel on that window, it inputs the name entry as a blank instead of just skipping entry altogether. Since this window appears in the browser, it also means you have to click back into the window to take control of it again (hence I might be mistaken about the UI requiring mouse input).
The music is pretty nice, and the sounds work for what they are. It is a little barebones and gives me the vibes of a student project, but it all works for what it is.
The graphics are very mixel-y, with lots of pixels of different sizes occupying the screen. The mixels make the game look especially amateur and unpolished, and the lack of animations on the playable character adds to this.
With that said, the core gameplay is very fun and it's relatively easy to get the hang of. I especially like the warnings on the right of the screen telling you when a bomb is incoming! This was very fun, but very unpolished.