Bustin' make Luigi feel good.
Ironically the original Luigi's Mansion was going to have some sort of 3D implementation on the GC but this was too expensive for Nintendo at the time so it makes sense the sequel would be on the 3DS using the 3D effect.
Professor E. Gadd's been researching the undead in his lab with the help of some friendly ghosts but suddenly it appears the Boos are causing mischief again stealing a magical entitiy called the Dark Moon to turn the other ghosts bad(?) and the Professor calls up Luigi to help him out again. He gets an upgraded flashlight and Poltergust and is sent off to do some ghost bustin.
This is another example of expanding on a sequel without ruining what made the original fun. First off, this really should be called "Luigi's Mansions" because you actually go to several different haunted houses. This is the closest Nintendo has gotten to a point and click adventure game. As you explore each room, you'll usually go through the same motions. 1) Shake an object 2) suck it with the vacuum 3) shine your flashlight 4) shine the rainbow light to find invisible stuff.
If I had one complaint about the gameplay, it's that the rigid mission structure doesn't allow for much exploration on your own. Often you'll get calls from E.Gadd nagging you about stuff when you just want to find that hidden gem or Boo and it would be nice to be able to explore freely as well as do the missions instead of being warped back to the lab each time. Also there are a few sections where you're forced to use the gyroscope to go across narrow beams. This is annoying.
Unlike Mario, Luigi is allowed to have a bit of personality namely that he's a scaredy cat. But it's funny watching him stumble around, pushing forward despite his fear and humming along with the in game music when you stand still. Also this is one of the nicest looking 3DS games and one where the 3D feels like a nice touch.
Surprisingly this has an online multiplayer mode as well. You and 3 other Luigi's of different colors have a short amount of time to find as many ghosts as possible. My experience wasn't bad and lag free though I did have trouble finding an available match that hadn't already started.
In conclusion, Luigi's Mansion: Dark Moon is definitely worth owning on your 3DS, even if you weren't a big fan of the original, this one is a major improvement. Now when it Luigi going to fight Gozor?