I've played through the game already. Loved the early parts - it's sort of like Diablo in FPS form. Sure you can't call it a true RPG, it's really a hack-and-slash, but different enough from an FPS to be fun. I don't usually play either FPS or RPG games, but this one had me hooked for a bit. Looks very nice, too!
Later parts of the game disappointed me a little, mostly because they forced you into an FPS dynamic, rushing you through huge swaths of the map very quickly and in a linear one-way path. And try as it might, it's no Half-Life at that. Wish it'd stuck to a more free-roaming approach.
And no spoilers, but the ending pissed me off to no end. Once I stopped being angry about it, it actually made sense to me and all, but my initial reaction... boy oh boy