Very cute pixel art, and the music goes really well with it too. I also like the way you designed your levels around the very limited controls. There are parts where you have to jump in order to hit a block and turn around, which I thought was a very clever trick. Overall, the game is very simple but also fun and satisfying to play.
My main issue is that I don't really see how this game ties into the theme of time. I didn't actually know what the numbered boxes did until you mentioned it further down in the comments. I thought you had to hit them in order or something until I saw multiple ones with the same number. I think you could've been more creative with the time theme, like maybe boxes that slow down or speed up time (and thus speed up the character.) Also, a quality of life change that I'd make is provide an option to restart the level when I beat one. There are levels where I missed the red gem and I would've liked to try again, but it throws me into the next level immediately.
Great game overall, I had a lot of fun with it. I got a time of around four minutes and 35 seconds.