Let it never be said that Konami can't smell a quick buck.
In 2001, Metal Gear Solid 2: Sons of Liberty blew everyone away with amazing gameplay (and left everyone mystified with the confused and confusing story), and quickly became one of the best reasons at the time to love or hate the PlayStation 2. Whether people loved it or hated it, they seemed to really love to talk about it.
Flash forward to the end of 2001, after the release of the Microsoft Xbox, a rumor started. (The rumor has been occasionally attributed to or blamed on Gamespot, although it may have come from elsewhere.) Whoever came up with it, rumors were flying about Metal Gear Solid X. If rumors were to be believed, this project might be an Xbox port of MGS2, or an alternate scenario, where the player plays through the Big Shell chapter doing Solid Snake's part of the mission rather than Raiden's, or even an update of Metal Gear Solid using the MGS2 engine.
Konami was listening, the rumors were right, or Hideo Kojimo is predictable, because November of that 2002 saw the release of Metal Gear Solid 2: Substance, which turned out to be a little bit of all of the rumors. (Of course, it came out just in time to be overshadowed by Splinter Cell, but this is neither here nor there.)
The first release, for the Xbox, was a minor success. It wasn't a perfect port, as illustrated by framerate drops at times like the rainstorm on the Tanker, but it was good enough as such things go. Plus, MGS2 did drive sales in the crucial 2001 Christmas season despite some critical backlash, so Xbox owners were happy to have the previously PS2-exclusive title.
Unfortunately, the PS2 and PC release, four months later, did not fare nearly as well. MGS2 had been available on those platforms for nearly a year and a half, and was especially readily available on the PS2 after a Greatest Hits rerelease. Few people who wanted the game didn't have it already, and those who did want it could get it for $20 (or less). Substance was released for a full $50, like any new title, and did poorly as a result. It has seen enduring sales as a catalog title, though, as the price difference between it and the original has disappeared.
All told, Sons of Liberty, the main scenario, is still the real attraction. There are some interesting additions, however, some of them minor modifications and some of them completely new game modes.
All of the versions of Substance have all of the difficulty levels, listed from easiest to hardest: Very Easy, Easy, Normal, Hard, Extreme, and European Extreme. (Some versions of MGS2 were missing some of these modes.) There is also the option to play only the Tanker or the Big Shell, instead of both in succession. (There's little reason to do this, but there is the option.)
Some minor modes are added to the Special menu. There is a Casting Theatre, for "recasting" the cut scenes, by switching out the characters. It's certainly an....interesting sight to see Otacon facing down the mass-produced Metal Gear RAYs. A Boss Survival mode is also added, with the traditional face-down-all-the-bosses-with-one-life-bar boss rush challenge.
The Missions screen is the meat of the additions to MGS2:S, and is done in the style of Metal Gear Solid: VR Missions. There are a series of missions, ranging from simple missions teaching infiltration and targeting to very elaborate missions involving bomb disposal. There are also some weird one-offs, including a sniper mission defending Meryl (or a plate of curry, depending from incoming guards), or a confrontation with a giant guard with spines like Godzilla. Solid Snake and Raiden can be chosen at first, but Raiden Ninja (Raiden in the Cyber Ninja outfit), Raiden X (X-rated Raiden, with his hand placed strategically), Plisskin, Tuxedo Snake (Solid Snake in a tuxedo), and MGS1 Snake (Snake with his low-poly MGS1 character model) can be unlocked by finishing the various missions.
The Snake Tales were the most hyped, and accordingly are the most disappointing, part of Substance. They are a series of alternate missions starring Solid Snake, and originally promised to explain where Snake was during the Big Shell scenario, as well as what happened in between Metal Gear Solid and MGS2. Unfortunately, all of the new dialogue is delivered as blocks of expository text, and all of the environments are reused from the original Big Shell missions (and a little bit from the Tanker, and a little bit from the other VR missions). They don't quite deliver all of that, as they conflict occasionally with the timeline of Sons of Liberty, but they are entertaining if taken as high-difficulty alternate missions instead of extra story. Finishing the Snake Tales doesn't unlock anything, and they are all equivalent of Extreme difficulty (including no radar screen.)
A Wrongdoing, the first mission, is set on the Big Shell and reprises listening to the hostage's heartbeats and the confrontation with Fatman. It seems outside of the Sons of Liberty timeline, entirely, but features Fatman, Richard Ames (brother of Nastasha), and an agent named "Jennifer," in a nice tip of the hat to Metal Gear.
Big Shell Evil covers Snake's half of the Emma Emmerich rescue, with Raiden excised entirely. Walking across the oil fence is gone, replaced with some extremely difficult runs escorting Emma through the struts of the Big Shell to a confrontation with the Harrier. This is probably the weakest of the scenarios, as it involves escorting Emma, a reprise of the lamest of MGS2's bosses, and a patchy and pointless story.
Confidential Legacy reprises the hallway fight with the guards on the tanker, and retools the confrontation with Olga as a confrontation with Meryl. Naturally, this explains what happened to Meryl in between MGS and MGS2, as well as explaining some very confusing relationships between her and Campbell. (Not as weird as Otacon and Emma's relationship, but close.) This is probably one of the strongest scenarios, because it's basically the Tanker scenario ramped up to a ridiculous difficulty level. The ending is a downer, though, even without killing Meryl (Snake will have the USP and the M9 at this point, and can use lethal or nonlethal force.)
Dead Man Whispers is a showdown between "Lt. JG Snake Plisskin" and Vamp, explaining where the Lt. JG Plisskin identity came from. It fills in some of the background of Dead Cell as well, but doesn't really go anywhere interesting. It's more rehashing of the Big Shell, but isn't deficient in any serious way.
External Gazer is freaking weird. It starts with going to the Big Shell to take a picture of a monster named "Gurlugon," who turns out to be the Guard-zilla from the alternate missions. The VR simulator turns out to be a multidimensional portal, Snake gets trapped in Raiden's body, Olga and Solidus are lovers in an alternate dimension, and nothing makes any sense at all. It's obvious that Hideo Kojima is parodying himself at this point, as Rose and Jack (Raiden) are introduced as "children of darkness on whom is focused the combined hate of the entire universe." The final fight is Snake vs. Solidus, made doubly difficult by the fact that Snake is unarmed.
After finishing the main scenario, Boss Survival, or any VR mission, a code pops onto the screen. From December 19, 2002 to October 21, 2003, players all over the world could enter the code into a form at http://www.konamijpn.com/mgs2_sub/ to be ranked with others who had finished those modes. There weren't any awards or anything, to my knowledge, but it was interesting to see some of the insanely short times.
The last addition, and certainly the least, is exclusive to the PlayStation 2 version, and it's not worth much. It's a demo of Evolution Skateboarding, Konami's exceedingly mediocre skateboarding title. Snake and Raiden are both playable, skating on different parts of the Big Shell. (They each have only a single stage, and most features are missing; this is only a demo.) It's kind of a shame that Evolution Skateboarding is a mediocre engine to start with, because both stages are interesting in a ridiculously-long-grindheavy-trick-lines kind of way, and Snake's remix of the MGS title theme and Raiden's remix of the Big Shell theme are actually quite listenable. The only other fact of note is the disbelief leaked screenshots caused, as nobody knew what to make of pictures of Solid Snake on a skateboard.
Metal Gear Solid 2: Substance was developed by Hideo Kojima's team at Konami Computer Entertainment Japan (KCEJ) and published by Konami. The game was released in the US for the Xbox on November 5, 2002, for the PlayStation 2 on March 4, 2003, and the PC on March 25, 2003. All three versions are rated M by the ESRB, for blood and gore, partial nudity*, and violence.
The packaging is influenced by the "big secret," the fact that Raiden is the protagonist instead of Solid Snake. The Xbox version has "METAL GEAR SOLID 2," with the letters in tall, black sans serif capitals and the number in blue, with a white-letter "SUBSTANCE" on a narrow black bar, superimposed over a sketchy ink-and-pencil version of Solid Snake pointing a silenced handgun at the viewer, with a vague cityscape in the background. The disk has a similar image.
The PS2 and PC versions were the second release of MGS2 on those systems, so the secret was out, so to speak. The cover for these two versions has the same title design, superimposed over a chest-up sketch of Snake holding the same pistol in the foreground, a full figure of Raiden a bit further back, and a very faint background sketch of a head-shot of Solidus looking contemplative.
* - It has this rating due to a short sequence, later in the game, with Raiden running around naked with his hand covering a...ahem...tactially important part of his body. According to The Document of Metal Gear Solid 2, the character model is as biologically impaired as a Ken doll, though. It figures.
Metal Gear || Metal Gear 2: Snake's Revenge and Metal Gear 2: Solid Snake || Metal Gear Solid (The Twin Snakes) || Metal Gear: Ghost Babel / Metal Gear Solid GBC || (The Document of) Metal Gear Solid 2 (Substance) || Metal Gear Solid 3: Snake Eater || Metal Gear Acid