The only issue problem I see is this won't really expand that much on the game. I thoroughly enjoyed both portal games, but with this it just seems like it's going to be an addition to the time spent playing the game, not an addition to the game. The most enjoyable part of Portal2 for me was the tone and atmosphere you felt as you went through the game. The heckling from either GLaDos or Wheatly as well with the muscial composition really enhanced the game for me. This just seems like it's going to be people trying to throw the most difficult to impossible levels together.