Gensokyo Tower Defense is a simple tower defense game taking place in the Touhou universe. This doujin game features 5 playable characters each with all completely unique towers and playstyles. There are a basic 4 difficulties among 9 playable stages with different styles of enemies and wave patterns, several extra play modes.

Three of the characters and four of the stages are unlocked from the start, other modes, characters and levels must be unlocked over time by completing the challenging normal mode or higher.

The game comes with an editor to create your own waves, however this editor and the main game may not work without the japanese locale installed.