Oh, we aren't playing seriously that day in frostclaw (Easy difficulty), we died a lot but sometimes we just wanted to explode a hyper grenade in the face.
We spammed a lot of them all around the map.
About difficulties, really, i can't feel the difference, except of the Pupae Meteors of Infernal Falls (Hard/Unreal,Co-op only).
In SP i can't almost feel the difference since i am the quickload/quicksave guy, i just lost like 1000 armor or a few ammo when finishing the map, what if i don't save? Maybe there i can find differences in the gameplay. (I only have played Easy and Unreal in the SP campaign.)
So i think that you would modify difficulties and look like this. (From easier to harder, SP and Co-op.) (lol ignore this crappy idea.)
- Easy: Lets kick some ass! (Very Low frequency.)
- Medium: I want a little challenge. (Low frequency.)
- Hard: I want some challenge man! (Between Low and Normal frequency.)
- Unreal: I want challenge man! (Normal frequency)
- Easy Co-op: Oh yeah, this actually harder than the Unreal difficulty (Maybe), play with more players then you lazy! (High frequency + a few Minibosses.)
- Medium Co-op: Damn, this is hard! (Higher frequency + a few Minibosses.)
- Hard Co-op: Holy f*ck it hurts! (Very High frequency + some Minibosses.)
- Unreal Co-op: WHAT THE HELL (Extreme frequency + Minibosses.)
- Nightmare Co-op: This difficulty doesn't exist, anyway.

(Nightmare Frequency + tons of Minibosses even bosses. lmfao.)
For Soul Storage, it's pretty hard on easy, i tried to get to the end of map but monsters spawned and killed me with my 750 armor all the time, i recommend to low it.
Yesterday i played Infernal Falls at Unreal Co-op difficulty, i tried to get positive score but slowly i am starting to have negative, i explored every place, KILLED every pupae which spawns from these meteors, i was hours playing there, joltstones helped me with pupaes, i have also used the Co-op only Energy Assault Rifle on them, in the huge blood pool, there were hundreds without framerate drop! Killed all them! Got a lot of score but then killed by the tough dudes from these hell hoes, killing smaller guys does help, they drop stuff and armor but do not keep killing all the time there! The big boys can spawn and kill you in few secs!
Next time i will choose Hard if there is a difference.
P.S: Tachyon chargers in 16th map in Co-op? it would be cool!
EDIT: We tried frostclaw in easy again, somehow, we got positive score, until i exploded a hyper grenade in my face accidentally at the end of the map, it should be easier IMO, how about the harder difficulties?
We completed frostclaw in mid-hour, very fast! Until the big dudes spawned.
EDIT 2: Got a LRPC!