Game genres are a double-edged sword in that we now find it so easy to pigeon-hole games. It's got cars in it, so it must be a racing game, or it focuses on lots of gunplay, therefore it must be a shoot-em-up. Titles that transcend these borders often get slotted into the arty, abstract or 'definitely not going to sell over ten thousand unit' category, but these are the titles that get rave reviews and industry awards then fall into obscurity.