I liked the atmosphere of the game and the way it makes you think about your next steps. Upgrade system adds motivation to play it again and again so finally you know you will be able to beat the bosses.
Noticed that sometimes hero gets stuck between two adjacent boxes when running on it. Probably because of two different colliders, not sure how it works in godot. Anyway, jump always helps so it's not critical issue.
Generally, the game is good and fun to play. Great job!