Here is the full list of all 11 Ghoulboy achievements worth 1,000 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox One.
Big Sword
Kill the first boss
Kill the second boss
Complete 10 levels
Pass the Samora level
Finish all the levels
Die 30 times
Obtain 5000 coins
Buy all upgrades
Throwable 100 objects
Complete 20 levels