Metal Gear Solid: Portable Ops Plus is an online focused add on to the original Portable Ops. Introducing new weapons, soldiers and maps aswell as new game modes and an internal chat system. Also included was a new single player campaign known as "Infinity Mission". Having no story, infinity mission pitted your selected team of 4 soldiers against random enemies on a random map with random items scattered around. The object was to make it through all the stages to unlock rewards and gain experience. MPO+ is also the first time Players were able to control Old Snake.

This promotional version was only released to stores and magazines for reviewing. The myth about Promo versions is that they're only samples of the game. This is not the case. The promo versions are actually the full game in their own unique packaging.