Touhou Monjusen ~ Bubbling Imaginary Treasures is a vertical danmaku shooting fangame developed and published by Gore, who had previously released Frantically Forbidden Fruit and Re.Phantasmagoria of Imagine Breaker.
The gameplay derives elements from several official Touhou games, such as Double Dealing Character, Wily Beast and Weakest Creature, Hidden Star in Four Seasons, and Subterranean Animism. The game features five playable characters with three partners each. Your player's weaponry depends on the partner chosen at the player select screen.
The main game mechanic is the Assist Spirit Strike system. By collecting coin items dropped by defeated enemies, you fill up a gauge at the bottom of the screen. Once you have enough money, you can spend some of these coins by pressing C to activate an Assist Spirit Strike, the exact kind varying widely depending on your player character.