Carmageddon launched early. The promo version will be pulled after a day. I don't know if that means from the time it went up, or end of day May 10 which was the original launch date. If it's not available for your particular device you can try an app called market helper (must be rooted. not on play store) or an Android PC emulator like bluestacks.
Thanks for the heads up about Carmageddon. I definitely made sure to pull a copy. On a random note, I wonder if this will stay in our app archives? I have pulled full promos from Google Play in the past and those remained available for my future use.