This review is based on the NG version, I was willing to play the downloadable version on Itch.io, but the download was not available by the time I writing this, so...
I can sense the fun & appeal in this one, unfortunately the game is buggy & a bunch of upgrades are not good. I've struggle more than enjoyed because of poor performance, it slows down poorly after a couple of minutes. In some of the runs I experienced some odd bugs like: Most of time the gun will be shooting at random directions rather where I aiming at (making annoying when trying to kill close enemies & tedious). The blast of the explosive enemies sometimes their do not cause damage to the other ones. When I reached to one the celestial sisters, the dialog box could not get out of the screen, I pressed various keys but none would make go away and when I level up, I couldn't choose because the dialog box was on the way to press accept, then after a while, one of the upgrades suddenly starts spinning on his own. I tried to keep going but the bugs, poor performance and glitchy hud was on the way till was unplayable.
Leaving the tech issues aside, The upgrades are a hit or miss, Like, why have two upgrades that does the same thing (Bullet Thickness ++ & Bullet Thickness 20%). Also, what is the point to skip a level if I'm unable to store for the next level.
This one is just a idea but, perhaps it would be cool if add different weapons during gameplay, for example, sometimes enemies will drop a weapon that you could pick up, making the gameplay more engaging. Using the same weapon felt tedious for me and even relying on upgrades that completely change the stats of the gun didn't help much.
...