The movement feels nice. The upgrades system would probably be better placed in between "levels". Having additional levels - maybe with different places in the world, time of day, or country/town/city with increasing difficulties - would make playtime feel more rewarding. As it was I ended up just drifting back and forth from wall to wall shooting things and passively abducting people and wondering if the game had a win-state or not. Destroying the buildings is kind of fun but the inconsistency makes it confusing; also confusing because you don't seen to "gain" anything by destroying them, and it seems a little counter intuitive to be blowing people up if you're supposed to be abducting them. I also wish my missiles destroyed the ships or completely destroyed turrets (or if they do-more reliably so, because I couldn't tell if I was just missing/hadn't hit them enough or if they couldn't be destroyed at all). Final gripe is that the health bars and the reloading bars are visually confusing/unintuitive; I didn't realize I had a health bar at all for the first two thirds of the game. Perhaps switching the colour of the reloading bars to something less health-associated, like blue? It would also be nice if the alien ship shot lasers instead of missiles, so that there was some difference between the defenders and the aggressor weapons.