Gunster: Rain of Bullets was a 2D multiplayer action video game, created by Korean-based company NHN who in turn hosted the game using the North American portal named ijji. One other version of Gunster exists, named Gunstriker: Reloaded Bullets and is hosted at Hangame Japan.

Gunster: Rain of Bullets is a port from a Korean game of the same name and was hosted directly by Hangame, which both localizations were shut down. Minor differences exist between the two localizations, but the biggest difference is that they are managed independently of one another.