The retro games that you will be able to buy or play (insert coin style) in the soon to be released Game Room on Xbox Live Arcade won't have achievements, but the room itself does come with 1000 points you can grab by earning 56 various achievements. Some will require that you play quite a few of the retro titles though... Check out the full list of Game Room achievement at Inside MGC.
Game Room will see release next Wednesday.
