In the screen after the room where the splitting boss battle in Farfall took place, the bird can pass through the thinner part of a wall where the warp is located. This lets the bird walk through an invisible tunnel that exceeds the width of an entire screen. Continuing through this tunnel eventually leads the player to the start of StrangeCastle, where a save point is immediately visible.
The castle is green, with a grey interior. There are some yellow banners within the castle. The pink clouds against the white background of Farfall can be seen in some areas outside. On the first screen where the save point is located, a throne can be seen etched in the interior.
The remaining three screens of StrangeCastle are travelled through in a clockwise direction until the player reaches the save point from the bottom of the screen they started in. They all consist of double spiked crushers, which, unlike previously encountered crushers in the game, are indestructible. Depending on the area, the player must manipulate the crushers to fall or travel under them quickly as to not get hurt.
When the player reaches the same screen they started StrangeCastle in, they will see a heart door with a heart behind it and a Blue Orb. Collecting the Blue Orb increases the protagonist's toughness. If the player beats the area without taking damage, they can also take the heart.
- StrangeCastle has an unused track that was included in the game's OST.