The possibility to upgrade what you want and choose the difficulty was an excellent choice. Although, I do have to second RareChip on the combat; it was rather tough when I was stuck with only one direction to shoot to, but otherwise the combat was fine as well. Nice work!

I really enjoyed the exploration and being able to upgrade. I also liked that I was able to choose the difficulty. For improvement, I'd say the combat felt a little tough not being able to aim. Other than that, I enjoyed your submission!