How fun, tbh for me the upgrade system makes this game 100%. I'm sucker for upgrade mechanics like this, and I feel in this game while it was bit leaning towards being too easy, I do prefer it this way as it was challenging enough to navigate and control (in a good way) and destroy the enemies. Took me while to understand that they indeed were grenades, and would not blow up on impact. I also do like the certain variety you managed to put in here regarding the enemies / map, there was clearly distinct places such as the big open area with the big area bombs. I'm sure you have better names for them, but this is the best I got :D
Good stuff here, I got a D rank, which is fair, I bolted immediately when I got enough scrap lol.