Ok guys, I've manage to dug up YouTube to find out how to go over this episode, and it seems quite tricky because the door is hiding behind. I won't be able to see that door if I don't change all the bricks to coins. Other than that, the entrance that leading to the pipes that will channel to the miniboss is hiding ABOVE the screen, so I kinda lost direction. It's matter of how familiar with the map, and generally I spent more time digging the way to miniboss. Note that yesterday I did attempt this episode, but in the end ran out of time. Today is not any better despite I already have a general idea of how to pass this castle.
▶️ DTube
▶️ BTFS