The game is more like an adventure game to put it in common genres. Most of the game is spent walking around, finding clues, and going to bed to start again the next day. I'm not sure if you've read about the QTE(Quick Timer Events), but they require you to press a button within about a second to do certain things, mostly fighting, but is used for a few other things as you'll find out. These sequences are really quite amazing, and are awesome to watch, provided you make sure you hit the right buttons. Then there is the free fighting, which I'm not too big of a fan, but is pretty sharp in it's own right. Very fun when you get surrounded by 5 guys in an empty parking lot, only to kick each and everyone's ass, then MAKE one tell you what you want to know. Then there is the "metal gear solid" scene. That's pretty cool.
Everything blends together, and even though I'm only through half of the game, it's already one of the better games I've ever played. The time element makes the game though, as you have to watch the time to do certain things, and shops and bars only open at certain times. That's the most awesome part of the game. It makes it more 'real'.
It really can't be described as a Grim Fandango game, nor can it be described as an RPG, because it's just not. It really has succeeded in creating it's own genre.