It took me a little bit of time to get used to the gameplay. It feels more like a FPS with roguelite upgrades than a survivors-like. I was a little confused why I died the first couple of times; I think it was because the enemies were translucent, while their gems were opaque, so I thought I was supposed to walk into them to collect the gems, not knowing they were enemies. Later on, I somehow died by enemies that spawned behind me? I'm not sure what happened.
I liked the upgrades, although some of the choices seemed like it would increase the difficulty instead of making me stronger, e.g., making enemies have more hp or spawn more quickly. I'm not sure why I'd choose that over upgrades?
There was also one time when I had 2 upgrades in a row, and I think something odd happened there.. I don't remember what exactly though, maybe the game continued on or something?
Overall, I think distinguishing the enemies from collectibles would be a great way to improve the game!