I've spent about two hours on it, and I've had a great time. I love the music and all the sound aspects. Also, the old-school aesthetic reminds me of some PC games I used to play in the early 2000s.
As others have commented, the game feels somewhat labyrinthine, especially because many paths (maybe too many) are blocked until you find the necessary upgrade to pass through. Perhaps the issue is that the rooms could have more distinctive features, like different enemies or different types of blocks. Maybe making the aesthetic of the map change as you progress downwards, so everything can be more identifiable. It's appreciated that you can walk while looking at the map.
I like that it has a story and the part in the city, although I would like to be able to return from time to time; I don't know what upgrade is necessary to do this. So far, I've only obtained the dash and the double jump.
Anyway, it's a great entry, with some things to polish but quite fun.