They mentioned anything like an endless round of mob spawns type mini-game?
I've seen this in bastion and they have one in DoW thats pretty addicting.
I think it'd be interesting to have one that progresses extremely crazy where it becomes very packed with difficult mobs (possibly from Inferno). Reward for surviving great amounts of rounds leads to increased temporary loot find or what not. Just a fun little addition that I think is perfect in hack n slash types of games.
What do you guys think?