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.
Won 30 Medals
Won 5 Time Spender Medals
Spent 8 hours in your arcade playing games
Won 27 Medals
Won 10 Survivalist Medals
Won 10 Point Buster Medals
Reached Level 5
Won 24 Medals
Filled a Room in your arcade
Won 21 Medals
Spent 4 hours in your arcade playing games
Won 18 Medals
Won 15 Medals
Won 5 Point Buster Medals
Won 12 Medals
Won 5 Survivalist Medals
Won 2 Medals of each type (2x Point Buster, 2x Survivalist, 2x Time Spender)
Played a Friend's Game Cabinet
Won 9 Medals
Won a Medal of each type (Point Buster, Survivalist, Time Spender)
Reached Level 2
Visited a Friend's arcade
Won 6 Medals
Sent a Challenge!
Placed 5 arcade Decorations in your arcade
Placed 5 unique Themes in your arcade
Placed 1 Decoration in your arcade
Placed a Theme in your arcade
Activated 1 Mascot in your arcade
Won 3 Medals
Won your first Medal!
Beaten your own High Score in a game, while looking cool!
Placed a Game Cabinet in your arcade
Visited the Showcase Arcade
Theme an entire arcade with unique Themes
Win a Challenge
Win 10 Challenges
Win 20 Challenges
Play a game for 1 hour continuously
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 10 Medals of each type
Win 20 Medals of each type
Win 10 Time Spender Medals