I done well until i instantly lose to the black dropping dot. This game should be more balanced for sure. I'd like to see different kind of bosses, so while you beat first the harder one appears. Safe room - upgrades are fine but i though it just drops the game flow. Maybe on the game there would be small screen which appears on the game screen an then you can pick up 1 upgrade same time you play game. Or player would be able to pick one or more upgrades each time the boss has defeated, and other upgrades disappear out from the room as in effect. Game could also have a small setup time while on the start (intro, or "boss appearing" or something like that while the game starts too fast for now)
It's hard to stop to shoot. Then I realize there are other way to defeat boss: first I reach the front of the map, and then I load all bullets at the enemy, and repeated this cycle: It was cool while it combined the moving phase and shooting phase. Otherwise there would be a walk forward and shoot at the same time. Graphics (as well the theme) are pretty dark here, which is very good or very bad. This would be cool to play with someone as in multiplayer mode. The map scrolling speed would be a bit slower i guess.