Here is the full list of all 19 Wandering Skies achievements.
Finish the first 3 levels
Finish the first 6 levels
Finish the game
Finish a level without dying
Finish the game without dying
Fall 10 times in the hub
Be killed by every mean possible
Pick up all possible types of gun
Use the rollback for the first time
Finish a level with all collectibles
Finish 3 levels with all collectibles
Finish the game with all collectibles
Charge a shot during 60 seconds
Finish the game without any collectibles
Break 50 pots
Destroy a projectile with another
Finish a level without taking any checkpoint
Finish the game without dying, with all collectible and without taking any checkpoint