Throughout Mogeko Castle there are numerous items Yonaka can pick up, collect, use and interact with. Many of them, such as Prosciutto, Peppers, Seaweed Chips, and Porn, serve no real purpose other than to be collectibles and give the player insight into the strange, perverse, hedonistic, and gluttonous lifestyles of the Mogekos living in Mogeko Castle. Some items, such as canned beverages on the train platform, are quirky inside jokes referencing Deep-Sea Prisoner's other creations.

Other items, such as the knife, are necessary for Yonaka to escape the castle, and can be used to kill Mogekos that get in Yonaka's way. Killing the almighty 7 Mogekos will grant you an indifferent ending.