The game's English name, Boktai, is a combination of the words "bokura" and "taiyou", from its original Japanese name.
The game's cartridge was unique for its time, as it had a built-in solar sensor that is mandatory to play this game. Exposing the sensor to sunlight affects the gameplay greatly, which is a key feature. For instance, the player gets ammunition for the solar gun and enemies are either easier to defeat or avoidable. Without sunlight, the environment is dark and enemies are much stronger, and the player has to avoid any enemy encounter.