A glittering galaxy awaits inside! If you want treasure, get ready to dig! A retro-colorful dark-pop exploration STG fantasy! Touhou Houtenkyou ~ Treasure Castle Labyrinth is a fan-made Touhou Project game made using the Touhou Danmakufu ph3sx shooting game engine. Treasure Castle Labyrinth was first conceptualized as a hypothetical Touhou fangame by Iroboshi of iroirodou around the release of Undefined Fantastic Object, and was later made into a music album in 2014 with the help of Pesot.jp/. Development of the Treasure Castle Labyrinth game began in 2018, spearheaded by DOGSDAY. In 2020, the members of both iroirodou and DOGSDAY came together and established a common circle dedicated to the game's development: UWASA Enterprise.