Metal Gear Solid: Portable Ops Plus is a multiplayer-focused expansion of 2006's Portable Ops. It is a standalone disc, though owners of the first title are free to transfer characters. The "Plus" aspect translates into new soldiers, updated play modes, additional maps, and an experience-based progression system. The original game's Story Mode has been dropped in favor of an Infinity Mode, which offers 50 stages of sneak-and-shoot action. While the primary goal is to find your way toward a randomly generated exit without alerting guards, a secondary objective is to neutralize enemies so they can be added to your multiplayer squad.

As in the original, the game supports Ad-hoc and Infrastructure wireless modes. A new Shooting Gallery option has players on opposing teams earning points by firing at star icons scattered throughout a map. Also new is the option for new players to hone their skills with each weapon type in a series of training exercises against the AI. Five additional online maps are included, many taken from Metal Gear Solid 3: Subsistence, bringing the total number of playable areas to 12. Other notable features include text messaging and adjustable parameters for each of the five multiplayer modes. ~ Scott Alan Marriott, All Game Guide