Each world in Cuphead has a bevvy of secrets to find and unlock.
Secrets For Inkwell Isle I[]
At Goopy Le Grande's tree take a right until Cuphead reaches an underpass. If Cuphead goes through the under pass he can cross to the other side.
After Beating All the Inkwell Isle I bosses, the chipped mug will move over so you can get a hidden coin in the trees.
Secrets For Inkwell Isle II[]
At Wally Warbles's house on the right area you will go to the Grim Matchstick's tower easily.
After getting all the rainbow bridges to come up, the girl complaining about losing a race will give you a coin.
Behind Baron Von Bon Bon, there is the 4th barber talking to him will open up a song from the barbershop quartet.
Secrets For Inkwell Isle III[]
Above Porkrind's Emporium, there is a hidden coin.
Talking to the fancy glove will give you one of two things IF certain requirements are met. If you have all P's on the Run and Gun levels, you will get the two strip filter If you have all A's or better you get the filter
Secrets For Inkwell Hell[]
Behind the staicase there is a hidden coin.r