Full list of all 56 Game Room achievements worth 1,000 gamerscore. It takes around 60-80 hours to unlock all of the achievements on Xbox 360.
Played a single game for 1 hour continuously
Themed an entire arcade with unique Themes
Won 10 Time Spender Medals
Won 10 Medals of each type
Won 30 Medals
Won 27 Medals
Won 5 Time Spender Medals
Won 10 Survivalist Medals
Won 10 Point Buster Medals
Won 24 Medals
Spent 8 hours in your arcade playing games
Reached Level 5
Won 21 Medals
Won 18 Medals
Won 15 Medals
Won 5 Point Buster Medals
Won 12 Medals
Spent 4 hours in your arcade playing games
Played a Friend's Game Cabinet
Won 2 Medals of each type (2x Point Buster, 2x Survivalist, 2x Time Spender)
Won 5 Survivalist Medals
Won 9 Medals
Won a Medal of each type (Point Buster, Survivalist, Time Spender)
Won a Challenge!
Sent a Challenge!
Reached Level 2
Won 6 Medals
Beaten your own High Score in a game, while looking cool!
Won 3 Medals
Activated 1 Mascot in your arcade
Won your first Medal!
Placed a Game Cabinet in your arcade
Filled a Room in your arcade
Placed 5 arcade Decorations in your arcade
Placed 5 unique Themes in your arcade
Visited a Friend's arcade
Placed a Theme in your arcade
Placed 1 Decoration in your arcade
Visited the Showcase Arcade
Win 10 Challenges
Win 20 Challenges
Spend 16 hours total playing games in your arcade
Spend 24 hours total playing games in your arcade
Spend 36 hours total playing games in your arcade
Win 33 Medals
Win 36 Medals
Win 39 Medals
Win 42 Medals
Win 45 Medals
Win 48 Medals
Reach Level 8
Reach Level 11
Reach Level 14
Reach Level 17
Reach Level 20
Win 20 Medals of each type