it was alright, i do have a decent amount of suggestions tho.
first off, i don't think incorporating the theme to the upgrades wasn't the best approach, it just makes the upgrading phase a bit useless as having 1 door doesn't change much of anything. if i could add something to that, i'd add a percentage of what upgrade the player would most likely get on each door (like "67% +2 Speed", "58% +5 Max Health") so the player can have an upgrade to target instead of being completely blind while still incorporating the theme to it.
second off, the gameplay wasn't really engaging and the map is too cramp with nothing in it. for the gameplay, i'd add more enemy types as well as a small knockback when the enemies get hit so the player can slow them down (knockback can be an upgrade), and for the map i'd just make it a bit larger with hallways and flank routes so the player can explore more of the area.
third off, it just needs more game juice, i'm not gonna mention all of my ideas for it but i'd recommend seeing the common methods of adding them and see how you can incorporate them to the game by yourself.
regardless, cool game!