Pros:
-enjoyable music
-fitting soundeffects
-fairly polished on a visual level
Cons:
-gameplay and appeal is crippled by the 1bit aesthetic (for example, some spikes blend in with the background, causing some unfair deaths. The main character blends in with background elements. The the tiles would benefit from a pattern, giving the character sprites black outlines would help prevent the blending and changing from pure 1 bit to having elements monochrome would help with the overall enjoyment)
-The Gameplay has no real stable ground (before elaborating, keep in mind that it comes from someone, who stopped after 1-29) The main mechanic of box spawning feels barely fleshed out with the only secondary mechanic being the doors. While it is meant to be a puzzle game, going into every level instantly knowing as to what to doesnt really help it, especially when the majority of this game's challenge comes from moreso precision platforming than what's expected. I wouldn't really mind it if there was more diversity (maybe boxes, that have special attributes. E.g a box that moves linearly would help with both styles of gameplay).
While there are some more flaws, these two are the most noteworthy of the bunch.