There's easy, normal, hard and delta.Playing on medium (default I think?), I will play some more and if it stays the same I will try a harder setting.
Keep playing it because, like I said, you're basically still in a tutorial.
I'm on normal and I'm on a bit that's probably meant to be quite easy but I've already completely run dry of absolutely all ammunition and am going to have to resort to using my fists against frigging aliens.