To conclude, it is indeed nice to see such a game on a platform like iPhone/iPod Touch. But while the game is packed with lots of extra content and has good replay value, the gameplay itself is repetitive. Hardcore Metal Gear Solid fans should simply avoid this as it strays quite a bit from the MGS experience.
For casual gamers, who've always wanted to know what Metal Gear Solid was all about, but either never owned the console or were intimidated by it, should definitely try this game and use it as motivation to play the real Metal Gear Solid games. Is it worth paying $8 for this game? Probably not.