Interesting idea. At first, I did not fully understand where the “Cost of Progress” theme was represented in the game. I only found the explanation later in the GDD, because I did not really feel it during gameplay.
I think the game is missing some kind of narrative cue showing what the player loses by using upgrades. Even the player character does not visibly change. Since the game displays combat stats such as HP, movement speed, and attack damage, it feels natural to take every upgrade without feeling that you are sacrificing anything.
I think the core gameplay is good. It is a little repetitive, and once the player realizes that they can simply circle around the largest obstacle and that the AI is not very smart, the game becomes relatively easy to beat.
Art: Since pixel art was chosen, the pixel scale of the objects should have remained consistent. The player character is scaled up too much, while the background and other objects use smaller pixels. However, the shop artwork is amazing!
Music: I have to say that the gameplay music was probably the part that immersed me the most. :)
Good job overall. Integrating the narrative cost of the upgrades more clearly into the gameplay would make the game fit the “Cost of Progress” theme much more strongly.