Okay, so I made this account to get back to you because i had an issue with it as well - the exact same one in fact - the bottom right logo spins once or twice and then yeah- it fails -
SO WHAT I DID - was initially read the read me file that came with the install - and while you're not aware of this I solved the problem by getting the brand new nvidia PhysX drivers after uninstalling the one that I currently had installed.
Then: I launched the game and this whole amazing interface which was so different to Original Sin popped up!
Enjoy the game - this is how you'll work it - i tried compatibility and all that at first - but it was the Physx all along --
MUCH <3
You must know this account was created just to help you- By the by: CH[F]uck Steam and Gabe Newell