I really liked the concept and the progression system, but the game speed itself felt really slow. It was difficult to judge when I should shoot moving enemies from far away cause it would take my projectile so long to reach them, and it could also be difficult to dodge attacks just cause my ship felt so slow. I also liked the different enemy types, but think you could mix them up with multiple types per level, as is the enemies that explode when you shoot them were never a threat, whereas the enemies that wobbled up and down and shot a few bullets towards your current location were incredibly dangerous.
That all said, it's a very simple and clean concept with a lot of potential. I'm looking forward to seeing where it ends up at the end of the week.