For OneBit players, this guide will explain how to complete every Secret Achivement, alternatively you can watch the video of every Achivement.
Tutorial has a secret
Find the secret Evil Tree in the Tutorial, go up 4 Tiles and then 5 to the left. The Evil Tree now will appear, killing it completes the Achivement.
Can death defeat death?
As a Necromancer you have to transcend into a Reaper, get hit from another Reaper to get the Death status and then die from the death status while being transcended into a Reaper.
Kill a greedy Goblin
Kill a goblin, who collected 20 coins, you can see they collected 20 when they have red eyes.
Someone was here before me!?
Open a empty Chest.
The almighty one
For this secret achivement you have to complete all the other secret achivements.
Mortal curiosity
Go down instead up. To achive this you have to be pushed past the bottom of the screen, which will result in a death, by a cyclops for example.
Whos the boss now!
As a Necromancer, transcend into a Hydra.
Im so sorry! I didnt mean to
You have to make Cthulhu kill Morgana with his Tentacles.