My girlfriend and I just finished the core campaign, and we didn't even get CLOSE to beating it. Avoiding specific spoilers, we chose the "easy" (and dark, and really funny) way out of the situation, which has left our characters effectively useless for future games (which I'm kind of fine with if only because that ending was so funny).
Despite the fact that we were specced as a combat-heavy Roland and an investigation-heavy Daisy, we were an act and a half away from winning when Umordoth was summoned, and then basically powerless to do anything but whack him a couple of times and die the second he appeared.
And we were cheating! Like, a lot! If we'd just spent an entire turn fighting a monster and I drew another one, sometimes I'd just mumble to myself and put it away.
Some stuff I realized after playing that we weren't doing correctly:
- Skill checks can't go below zero
- My Daisy deck didn't have any occult stuff in it (misread the arkhamdb.com UI)
But I don't know if that's enough to explain just how badly we got our butts handed to us nearly every time. Are there any obvious things that first time players get wrong, or some good beginner advice you might have?