First off, I’m impressed you did this with just vanilla JS! I’ve used Phaser before and even that was a pain. I’m a professional software engineer and I still dislike making games without an editor!
As for the game itself, the art is cool and the animations are solid. The gameplay itself operates well and I didn’t find any bugs (a small thing would be that if an item spawns near the edge, half of the art is off-screen. That could easily be fixed by making sure the width of the sprite isn’t off-screen when doing item generation).
I do feel the game was missing one feature, like maybe a way to jump over certain obstacles or a different obstacle than a rock. Perhaps an enemy that slides across the screen.
Besides that, great game, thanks for making it!