I would like a game like Baldurs Gate. When in multiplayer mode, up to 4 people can play together, but the difference with the DS would be, they can also go off on their own. Once they leave a players screen, the map on the bottom screen shows where they are in the current area. This opens up a whole new way to play, as you could theoretically go for all the gold/reward yourself, making you enemies along the way. But your lack of teamwork could hurt you in battle. You could all work together as well, with two players going around back of a group of skeletons to ambush them as you draw their fire. I mean, really, the gameplay mechanics this opens could be endless. There could be stats at the end of each area, and what you did can change your alignment, such as evil or neutral. Hell, even Gauntlet would work this way.