A slightly underwhelming addition to a great game.
User Rating: 9 | Metal Gear Solid 2: Substance (w/The Document of Metal Gear Solid 2) PS2
I got this game cheap ex-rental as my first foray into the MGS series, and loved it. The first thing you need to ask yourself before buying this game is; "do you already own MGS2: Sons of Liberty?" If the answer is yes, there may not be enough additional content to be bothered paying again. However, if you answered no, you should check out this game immediately. Everything that made SoL great; the stealth, the graphics, the characters (though not necessarily the plot), the game mechanics make a triumphant return, however the 300-or-so VR missions and the snake tales missions, while a nice diversion, aren't really enough to justify another purchase. For those who haven't played the original however, this is the definitive version to get, with some nice bonuses to pad out the reasonably short main game. Less-than-inspiring as these extras are, they turn MGS2 from a must-have to a why-don't you already-have-it. You'll have a blast, but it won't differ too much from the previous experience. 
