There is a cave called "From Cave" that holds many references to Demon's Souls.

• The cave itself is a reference to the company, From Software, who developed Demon's Souls. They also published 3D Dot Game Heroes in Japan.
• An item can be found inside called "Sticky White Stuff," which is a reference to the in-game item in Demon's Souls of the same name.
• Two messages can be found on the ground, one saying "It's safe here," and "I'm in trouble! Please recommend this message!" referring to the player-left messages.
• A "Hero's Soul" can be found lying on a corpse, just as in Demon's Souls.
• There is an NPC who says "Come on guys, this game isn't THAT hard..." referring to the overwhelmingly high difficulty of Demon's Souls.