I enjoyed playing your game although I really did not figure how upgrades work. I think all I did was throwing wood into the fire and increasing the difficulty but I could not figure out how to spend wood for upgrades.
I like the visual and the music and how the character feels. The little jump when you attack is a nice little detail.
There were some bug like missing enemies or wood that is dropped inside of the wall, but I'm sure you can fix that.
I didn't bought any upgrade so I don't know if the weapon will change but what I think would really make the game even cooler would be a different weapon. The blast is nice but it's not really interesting to you. You just spam the attack key and try to keep your distance. Maybe think about some projectiles like in Binding in Isaac. This could fit your game pretty. Just an idea :)
Overall a nice game and when the bugs are gone at some point I will check it out again and buy some upgrades. Good job!