Official story and features:
"After two decades of playing second fiddle to Mario, little brother Luigi is headed straight into the thick of things, and his nightmarish adventure is guaranteed to be one of the most spectacular and involving games ever created. (...)
Now, the Miyamoto magic is working on the most powerful game platform ever and the results are frighteningly delicious. Luigi's night of fright takes place in a spectacular haunted mansion that is inhabited by ghostly apparitions. As Luigi searches for his missing brother, he enlists the aid of a paranormal researcher who is adept at capturing pesky and malicious ghosts. The ghosts are afraid of Luigi's flashlight, but poor Luigi is terrified of ghosts, which makes every step a challenge. Luigi's Mansion is filled with comic shenanigans, riveting gameplay and stunning graphics that showcase the Nintendo GameCube difference. It's all about fun..."
From Nintendo site
This game is.. Awesome! I've Completed it to the last boss twice now, and I'm itching to start again! I really want to know what happens when you beat Bowser, I've never got that far, but before you get that far it's awesooome, and what is that pretty mansion behind the creepy one? Wow, this game really gets you thinking, it scares you a little too :)
-- From Sophie Hickman
Luigi is my favorite of the two brothers and I love ghosts the perfect game for me.
-- From sunhookie