Here is the full list of all 11 ROBLOX achievements worth 1,000 gamerscore. It takes around 2-3 hours to unlock all of the achievements on Xbox One.
You played a Roblox game with 3 of your friends!
Played 15 different Roblox games.
You played a Roblox game for one hour!
You played 5 different Roblox games.
You played a Roblox game!
You joined an Xbox party and played Roblox.
You changed your avatar's look!
Rate 5 Roblox games.
Play Roblox 3 days in a row.
Play Roblox 10 days in a row.
Play Roblox 20 days in a row.