Here is the full list of all 13 Offroad Masters: Motocross Races achievements worth 1,000 gamerscore.

Full list of all 58 Halo: Campaign Evolved achievements worth 1,000 gamerscore. It takes around 25-30 hours to unlock all of the achievements.

Here is the full list of all 38 Another Crab's Treasure achievements worth 1,300 gamerscore.

Full list of all 41 Lil Gator Game achievements worth 1,485 gamerscore. It takes around 4-5 hours to unlock all of the achievements in the base game.