When it was released with the launch of the Nintendo Gamecube in 2001, "Luigi's Mansion" took both praise and criticism for being an a-typical "launch game" for the new system. Both viewpoints are valid depending on what type of gamer you might be.
Basically, this game puts you in control of the usually second-fiddle Luigi, who is searching for brother Mario in a haunted mansion full of Boos. Armed with a ghost-sucking vacuum device, Luigi must suck up all the ghosts and get his fellow plumber out of the house of horrors.
In terms of gameplay, this game gets old quickly. Basically, you just go around sucking up ghosts and getting keys to rooms to...suck up more ghosts. It's fun for awhile, but gets tedious after about the first 5-6 ghosts or so.
The presentation, however, is what makes this game still fun to play even 10+ years after its inception. The graphics are perfect for this type of game (cartoony yet clean), while the humor of many of the situations is pitch-perfect. Because Luigi is such a quirky character in the Nintendo cannon, there isn't that "Mario pressure" and thus the game developers were just able to let things loose and have a little fun with this one.
Overall, "Luigi's Mansion" is a fun game because of (not in spite of) its quirkiness. Younger gamers will especially love this effort, as the gameplay will never feel stale for their skill set. More seasoned gamers will just laugh at the presentation/atmosphere and take the goofiness all in stride. I'd give it 3.5 stars to be exact, but it gets bumped up to four full stars here because it is just so innocent and fun.