Ok so I am stuck in level 2. The first 2 swarms I usually survive (barely) but after papa sagrassi flies away a second time in the hallways I get attacked again and I mostly make that one too but there is a part where the hallway is a cross section and you get attacked from pretty much every side and I just cant seem to get past that part. And after about 20 tries it gets pretty frustrating. Everywhere I look they say they are easy to beat and maybe I am doing something wrong but it’s really not easy hitting them and alot of times when you hit them they dont take damage.
I have the PC version btw.
What I did was when I came to the cross hallways I backed into the hallway on your right, it is a dead end. Then I took care of the ones that came after me. After them you go back out into the middle to lure some more then back into the dead end hallway again. Repeat this till there are no more. I was having the same problems you were having till I did this. I have the PS3 version but Im pretty sure it should work just fine for you on PC. Hope this helps!
Thanks alot. That really helped. 
The best way to deal with the crawlers (as well as any swarm type enemies you’ll meet later) is the boson darts. After upgrading you’ll typically take out a whole pack with a single shot. Hooray for splash damage!
Thank you for the help. I have actually realised that my enemies where not taking much damage. After re-installing the game everything works better now. For some reason the proton pack was doing little to no damage to enemies. It may have also had something to do with the no-cd executable I was using at that moment. I tend to use them so I dont have to use the disks everytime.