This one was difficult to understand until I learned that every attack requires power points and you lose health when the squares reach the right. Would be better if you implemented a tutorial if you had time, which would explain controls and enemy behaviour. It's also kind of tedious to power up by skipping, especially when attack commands are randomly generated and there's too many enemies on screen.
I will say, this tower defence game if quite innovative for a Game Boy-style game even if it doesn't fit the jam's theme (like you said). The graphics are minimalist but they work for the kind of "tiny" game this wants to be.
Overall, keep up the good work.