A excellent multiplayer and a good single player make this a great game.
This game is a stand alone expansion pack for the original Metal Gear Solid Portable OPS (Or MGSPO for short) MGSPO was a impressive game with a few downsides like some graphic glitches that wasn't fixed in MGSPO+, but the multiplayer that was already great is now improved.
Some may say that the single player of this game is weak, but it's far from it, of course the single player in MGSPO was better but... It is still good, the bad thing is... it doesn't have a story, that's right you've read it, it doesn't have a story, you choose the difficulty (you start only with easy and work the way out to extreme) and then the game starts. Every time you play the game, you start at some random level with random objectives that is get to point "A" to point "B" but since enemies, location of objective and items always change you can play it for hours and hours and still be surprised with the AI that's pretty good but sometimes they make stupid mistakes. And the best of all sometimes the game change the objective to things like "kill all enemies", "survive for 5 minutes", Get to the objective with a time limit" and things like that. As you should know you can kidnap enemies and convince then to join you, but in MGSPO+ there are more types of enemies like the genome soldier from MGS1.
The Multi´layer is GREAT, the best i've seen on a PSP, 6 players can join in a deathmatch, team deathmatch, capture the flag, chat room, shooting gallery... But now you're probably thinking "geez i've already seen this in a lot of games!" but since you can use all the moves from single player this make very funny and tense moments, there are always people online, the only problem with the multiplayer are the hackers and cheaters, trust me a lot of then... Having the option to put 8 players would be nice...
Graphics 9.0
Excellent character models and textures, nice explosions, a lot of enemies in the screen without much framerate drops. There's a few graphical glitches that hurt the score.
Sound 9.5
Great ambient sounds and music that helps you to get in the climate, but full speech would be great.
Fun 10.0
Excellent multiplayer with lots of tense and funny moments, plus the single player called "infinite mode" will keep you entertained online and offline.
Gameplay 10.0
In the single player you can sneak or blast your way in, either way it is damn fun. In the multiplayer it is fast paced and funny, all you want in a game.
Replay 10.0
Infinite mode, boss rush and multiplayer will keep this UMD in your PSP for a long time.
Overall 9.0
If you can find the MGSPO buy it, but if you don't find it the MGSPO+ is great too!