Quite a fun game. The difficulty was maybe too low, I felt like most of the game could be finished without shooting once (which for Bullet hell is quite weird), since you have so much health you can survive a lot and each save point also heals you. Other than that the game was fine, some decent puzzless with really cool water mechanic. First time I saw the water, it really suprised me, since I wouln't even think about that, but It works very well. Both graphics and sounds fits well to the "post-apocalyptic / otherwordly" (could be both tbh :D) atmosphere.
Some minuses. I was really missing some animation, mostly on player.
Other thing I was missing was some kind of restart button. You could restart by dying, sure, but restarting with a click of a button would be welcomed.
One funny thing I noticed is that the shooting enemies has a range, unfortunatelly if you start shooting them further than that, they won't fight back, which makes defeating them a breeze.
Last thing would be missing exit menu or some other way to leave the game. Exiting through task manager is never a good sign.
Overall it is quite good game, level are well made, not too difficult, but not so easy that you would just run through all of them. The game has some fun mechanics, which can be expanded on, but for a shooter game it could be a little more challenging.