I'm so stoked for this game. I'll probably never use the multiplayer, though. Most of my friends think I'm crazy for owning a 3DS, and they sure as hell aren't going to buy one just to play Luigi's Mansion.
The big mystery to me though, is that the final boxart has a Nintendo Network logo on it. So since online multiplayer appears to be off the table, what gives? Online leaderboard? Paid DLC? DLC would be awesome.