Gradius Collection, known in Japan as Gradius Portable (グラディウス ポータブル, Guradiusu Pōtaburu), is a compilation of five Gradius games, converted for play on the Sony PlayStation Portable by M2. The games were reprogrammed to take advantage of the PSP's wider display, as well as allowing players to play each game in their original aspect. Four of the games were taken directly from the arcade game, while Gradius Gaiden was a Japanese only release for the PlayStation.