Here is the full list of all 10 Refunct achievements worth 1,000 gamerscore. It takes around 1-2 hours to unlock all of the achievements on Xbox One.
Finish Refunct in 8 minutes
Refunct your heart
Collect all cubes
Collect 14 cubes
Collect 10 cubes
Collect 5 cubes
Collect a cube
Refunct the world
Finish Refunct under 33%
Finish Refunct in 4 minutes