On July 17, 2007, Konami announced Metal Gear Solid: Portable Ops Plus, a stand-alone expansion of the original game, focused on online play. Among its new features, the expansion includes new characters such as Genome and Gurlukovich soldiers from MGS and MGS2 respectively. There are also new missions, tutorials for beginners, as well as a new single-player mode called Infinity Mission.
In Japan, Portable Ops Plus was released on September 20, 2007 in two formats: the expansion on its own and as a deluxe package that includes the original game and the expansion. The North American version was released on November 13, 2007. The European version was released on March 28, 2008.
The story mode within Metal Gear Solid: Portable Ops has been removed, and a new single player mode called Infinity Mission has been added, where the player must go through randomly chosen maps, looking for the advance point within the level, using the surround indicator to help them. This adds some extra difficulty, because the surround indicator could show an enemy, or the advance point. Within this mode, there are also Kerotan, which make a small croak sound, as well as briefly showing on the surround indicator with every croak. The game places an emphasis on online gameplay, with the modes from the original being used with their + counterparts, such as "Cyber-Survival+" and "Infrastructure+". During online gameplay, rookie players will have a rookie mark, reducing the damage they get, and increasing the damage they give, making online gameplay easier for less skilled players.
