The first part of the trilogy is the best. If you didn't play it, it's worth trying. Of course the graphic representation of character/monsters aged, but the mansion still looks good. Interface takes some time to get used to. Locking you in a house without any help made it great. Plus the emphasis on puzzles and narration element. The french CD version has some good voice acting, as most of the voice actors come from the theatre scene. The soundtrack from Philippe Vachey also builds a creepy mood, which is of course important in game such as this and is why I mentioned it in this thread.
The sequel has some funny/good moments, but it tends to be more action oriented. But it doesn't work really well, because of the camera angles where you can't even see the enemy, but he can shoot you. The problems with interface are even more evident, and they just make things worse, as we try using object on object and solve a puzzle, which are simpler than in it's predecessor. But if you want to beat the shit out of a pirate zombie goons as a Santa Claus with a frying pan, you should play it.
The third part is set in Wild West, and it is actually really good. There is more elements of mystery, puzzles and thanks to the setting that wasn't overused it felt more unique.The main letdown for some people was that despite having many places to visit, the player still had to go through a specific path like in a typical adventure game to move forward with the story. There are some enemies that you can kill, but many of them need specific items/actions to be killed.