My feelings on this are mixed. The auto-aim and auto-fire for both guns and abilities make the gameplay awfully dry. It's really only difficult before you get any upgrades; after that it's basically just running in a circle as you get faster and stronger over the course of the wave. A mode where you can manually use abilities and fire would be more engaging.
It could probably use more of a tutorial, too. It took me a couple of waves to figure everything out (not even everything; I'm still not sure what gaining corruption actually does) and I can see those with less patience than me getting frustrated by the lack of guidance or never figuring out that you need to pick up the puddles, check your upgrade tank after every wave, equip both guns &c. I'd also recommend removing a step from the upgrade process and just giving you one straight from the tank; if you forget to empty your inventory of all the alien parts you can end up picking it up but not getting it and the whole 'pick up this item, register it on your hotbar, then use it, then upgrade from the deploy menu' process could stand to be streamlined anyway.