Tutorial, World 1: Inkwell Isle 1
Not particularly 'hidden' but easy to miss if you care not for Tutorials.
- Head on over to 'Elder Kettles' and enter the Tutorial
- Run through it and pick up the Coin at the end of the course
This one unlocks after you've beaten all 'Inkwell Isle 1' bosses.
- After you beat them, go over to 'Axeboy'
- Talk to him and run through his dialogue *he will then move aside*
- Pick up the Coin within the tree's
World 2: Inkwell Isle 2
This one is unlocked around the 'Aviary Action' section of the world.
- Go up to 'Aviary Action' Walk around it and continue to your right
- Keep going through the shortcut and come out the other side
- Go back through the shortcut to your left and come out next to 'Aviary Action'
- Walk up to the 'Gingerbread Girl', talk to her and run through her dialogue
This one requires completion of a parry challenge.
- Talk to the Juggler on the East side of the world and run through his Dialogue
- Go into any level or boss and parry four times in a row before landing
- Return to the Juggler and run through his dialogue
Below exit to Inkwell Isle 3 is a green shack which will also have a coin in front of it.
World 3: Inkwell Isle 3
This Coin is hidden right beside the stand next to the Theatre.
The final hidden Coin is hidden behind the stairs outside the Casino, the Coin is to the left of the stairs.