Absolutely loved this. This is one of those games you play as a developer yoruself and think, "Oh damn, the competition out there is fierce!"
Loved the inventive item upgrades. The way upgrades that increase fire rate for every bullet fired encourages different build paths than just the standard damage and crit rate. Very fun itemization.
The extra features of the base didn't make me enjoy the game more, I think you guys could make this something you unlock further along, and once unlocked gate its features more. I was kinda just overwhelmed by it all and didn't want to play the game as much. A simpler system that unlocked more mechanics over time would have kept me around longer.
Maybe more obvious permanent upgrades akin to vampire survivor that increases drop rates of powerful things, increase exp gain, gives innate passive regen would all be things that would add lots of replayability in the short term.
Really great game!
Oh, almost forgot! I REALLY disliked that there was no damage cooldown, and you could die so insanely rapidly. It felt like the game relied too much on enemies running up to you super fast and just outright killing you. I would have preferred more bullet hell elements to ramp up the difficulty before these more "cheese" mechanics ended me. Seemed like the only ranged attacks enemies tried to hit me with were really slow beams that were easily dodged as opposed to true bullet hell.
I got pretty far one run and some super hard enemy just flew to me very fast and killed me instantly. Felt really cheap, like I feel like I should have barely survived lots of intense bullet hell type stuff before some uber creature just runs up and kills me instantly.