Very very cool concept. As an experienced helldiver I was calling down volley after volley with no hesitation. But yeah as others said, polish felt great, would love to see a full-fledged version of something like this.
I think it'd be cool to keep the power up type system, but maybe have a few different options for moves, and need to execute different moves for different enemy types. Also take the map and make it overhead? to track out more enemies? I really love this concept though.
