Except for team of really low skilled players. Is it challenging ? As a PvE of a sort map it's not really hard if you step-by-step do the right things, only players that think they can play solo ruin the game. I think that the NM mode should be way more harder that is now, implying that players should play on normal, veteran or hardened mode until they learn the basics and NM for extra challenge to hardcore NotD fans. I propose that the Nightmare runs should be at the brink of sure defeat so only players with very good knowledge and game-play could win it. Even if it's not implemented for the WoL version of the map, would be good to do it in the freshly made HotS. What's your opinion everybody ?