Here is the full list of all 28 Black Skylands achievements.
Defeat Horos
Get All Weapon Mods
Obtain Steel Condor Crossbow
Find All Chests of Gold
Defeat Ruth
Liberate All Islands
Defeat Kain
Defeat the Devourer
Defeat Rhoda
Defeat Blast
Get more than 17 000 Weapon Steel
Get more than 17 000 Ship Steel
Visit Swarm Territory
Get 50 Weapon Mods
Defeat Mort
Get more than 6 000 Ship Steel
Get more than 6000 Weapon Steel
Liberate 10 Islands
Find 10 Chests of Gold
Defend the Moth Village
Get more than 1000 Ship Steel
Find 5 Chests of Gold
Get more than 1000 Weapon Steel
Get 5 Weapon Mods
Defeat Crash
Liberate Mills Island
Liberate 3 Islands
Complete the Prologue