It's not quite hard, but there are a few things that can cause groups trouble.

First boss: Idiot check. Can you stay in the purple light? That's all that's really needed.

Second boss: Party check. Basically can the party adjust to the flow of the battle, avoiding the AoEs and working the boss down. Also a slight healer check since the first time I tried it I was massively undergeared and it showed (despite the fact that I'd used the same gear in the other dungeons up to this point).

Final boss: Tank/healer check. If the tank is undergeared here, it's going to cause problems. If the healer is undergeared, it's going to cause problems. If both are undergeared, you won't finish this fight.

Again, not hard per say, but it does have more to trip groups up compared to the other dungeons I've seen so far (which you can basically faceroll, except for maybe the last boss of Hakkuke).