I couldn't feel much of a difference on the first two hives either but beyond that you get a lot more cryptids spawning. It got pretty chaotic pretty quick. You also only get skill points for challenges and not from destoying hives. I think cryptids do more damage and are tougher. I played on casual first and noticed scouts were 1 knife kills right off the bat.
I can't speak for solo, but I have had 2 games of 4 player co-op, and so far have noticed:
In the first section (including the VERY first), there are multiple hunters, and scorpions, and LOTS of meteors. And I mean LOTS of Meteors. You'd think "cool" but no, electric fences don't even seem to kill them. Getting the "take no damage" challenge on the very first hive is extremely hard, near impossible I should imagine.
The most difficult thing is the fact that RICOCHET is on, so if you shoot your team mate, you get injured. At first I was "wtf is going on, I'm losing life randomly and no enemies behind/near me", then we all figured it out.
And of course, as bobby mentioned, you only get a skill point for doing challenges. Good luck doing the 75% challenge in 4 player. I can't imagine doing the 50% one haha.
Have a game of 4 player, then tell me if you can't notice a difference.
Be sure to have someone upgrade ammo straight away, someone armor, and someone team booster and then maybe feral. Team Booster makes a HUGE difference. The furthest we got was our second run, the hive just before the helicopter one. We got swarmed with scorpions and hunters. And I mean absolutely swarmed with them.
This would be very very tough WITHOUT ricochet on, so why they added that as well, is beyond me. Very weird that they did, but people did want it to be harder, and this is much harder.
Ok so we're in the pregame lobby and we're doing this then one of the party says "hey lets do HC" and we're like "yeah we got this" so we loadup and readyup.... get in game and are like "whats gonna happen?" then we plant the drill and all these cryp's come at us and we're like ( this is not devils first HC game unless yall haven't realized ) all of a sudden the has degenerated into ...... "wheres my skill points!!!! " and "what keeps hitting me???? and " how the hell can we take no damage when we have Hunters on Hive 1!!!!! Now by this time in gameplay if you have made it to Hive 2 YOU ARE DOING REALLY WELL..... " Ain't this great!? " says .... while reviving us for the 4th time by hive 3... we're like " why have you done this to us IW WHYYYYYY!!!!!!! thanks for reading and I hope to see all of you in a HC lobby soon GT- OFC Pugnax
In all seriousness IW could have given us a list of difficulty multipliers to check off. so instead of a reg match or HC match we could go into the custom game menu and click which ones we want to "activate" just like relics and depending on which one would give you a exp % boost just like relics..... turn on Ricochet and it adds 10% to score, disable hive skill point add another 10%, enable/disable cryp waves in between drilling add 20% etc.... you could even have a setting to adjust the strength and attack power of cryp's for more or less of a bonus %. well anyway I do enjoy the challenge of HC and will be some happy when I conquer it lol