Here is the full list of all 12 Imagine Me achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Begin a Dungeon in Campaign
Pick lock your first door
Falling into the Darkness
Jump on a Trampoline 100 times
Fall for the 15th Time
Defeat One Boss
Defeat Two Bosses
Defeat Three Bosses
Complete 50% of the Challenge Levels
Complete All Challenge Levels
Complete One Story Page
Move a Crate. Have an Achievement.