Really fun game and it plays well. I had some minor issues though:
Once I touched a portal and teleported before I wanted to, I would prefer if you have to press a key to exit since you could miss some loot.
There are a lot of weapon stats and they make sense but it takes a long time to comprehend which weapon is better. I would like to see their sell price, I think that will be an easy way to tell at a glance.
The graphics are nice but visibility isn't great. Sometimes I got hit by tiny enemies that I can barely see in all the carnage. Normally that wouldn't be a big issue, just be careful, but the game forces you to pick up runes quickly because they disappear otherwise. I get that it's difficult to do in this type of game but there has to be some kind of easy distinction between enemy and terrain/pickup like a different border or something because now they all kind of blend in. The UI is also a bit hard to read, numbers are small and there's a lot happening on screen AND you have to keep track of both your current ammo and total ammo. I'm really not sure about being able to run out of ammo, I'm not a big fan of that. I bough ammo whenever I can and I picked up the skills that let me have more ammo drops of that type and I still ran out of ammo on my main gun and died. And I was even conserving ammo by using weaker guns and taking damage because of it. It forces you to use multiple guns which is nice but I was already doing that because they all have different uses.
Anyway the core gameplay is solid and I enjoyed playing it, would just like to see some minor tweaks