I bought the ati 9600 too and I had no problems getting it from Steam.
The game is nice, but I dont see the "superb" physics engine being put to some gameplay use except when I piled boxes to reach tall areas, something Ive been doing in Zelda since Ocarina of Time. Actually I found many things inspired from Nintendo games, like raising and lowering the water level, there are many others but scape my mind right now.
Overall a nice game, the graphics are awesome and it really helps enhancing the atmosphere, but the game loads too often and the load time lasts too long, something that kills the inmersion you had in the game. Is kind of a minor problem but I think its worth mentioning.