You pretty much summed up all my thoughts about your game perfectly. Working on improving your art skills is good, but in my opinion gameplay and fun is more important. I'd much rather play an ugly game with really fun gameplay than a beautiful game with terrible gameplay.
As for the axe throwing, I don't think any of the player's moveset should be "allowed to be difficult". The player should feel like their moveset is working for them, not against them. There can be mechanics and special moves that are difficult to pull off, like in Celeste, but they should always be optional. If it's too hard to use, players will just not use it, which is exactly what I tried to do before I realized I had to kill all the enemies to win. If it's not necessary to use, then it's ok for players to skip the frustration if it's too much for them.
As I said in my first comment, audio is vital for player feedback, atmosphere, and making your game feel more alive. You should never skip it. I know you mostly made this to practice visuals, but I'm looking from the perspective of a real game.