Raiden is tasked by a reformed FOXHOUND to rescue the hostages, and is supported by the Colonel, and his girlfriend and data analyst, Rosemary. It is only later on in the game that the player finds out that Big Shell is just being used as a front for Metal Gear.
They, along with their leader who claims to be none other than Solid Snake, take the President, along with many employees hostage, and so new protagonist, code-name Raiden, is sent in. The unit, which is similar to that featured in MGS1, posses superior abilities which give them an advantage on the battlefield. In 2009, two years later, the game progresses as an oil-cleaning facility located on the Hudson River, named “Big Shell”, is overtaken by terrorist group Dead Cell. Solid Snake taking cover around a corner in the Tanker mission. Snake is blamed for the disaster and is presumed dead, and so begins Metal Gear Solid 2: Sons of Liberty. Old rival Revolver Ocelot (Liquid Snake) makes an appearance, ambushing and betraying his allies, claiming that he is taking RAY back, before destroying the ship. It is later revealed during this mission (spoiler warning) that the weapon is none other than a prototype Metal Gear RAY, and is being developed by the United States Marine Corps. The game follows on from the events of Shadow Moses in MGS1, with the player assuming the role of the legendary soldier Solid Snake, as he infiltrates a Tanker looking for a new type of Metal Gear. On the other hand, in the response tweet sent by the Metal Gear account, they do mention something about guests coming "next week" so maybe.The classic tactical espionage action game from Hideo Kojima and Konami, Metal Gear Solid 2: Sons of Liberty continues the epic story of Snake as he attempts to once again save the world. That April 30 date could just be a nod to the fact that Tom won't actually see his birthday as the Big Shell Incident takes place on April 29th.
I personally wouldn't get my hopes up for much of anything. It seems odd to be doing this much teasing for it to end up being nothing at all, but stranger things have happened. You can see some of the tweets below along with the interactions between the official Metal Gear Twitter account and Tom Olsen.
There is even one that seems to hint at a possible reveal on April 30th. The Tom Olsen account is posting a lot of pictures from around the Big Shell location. The account in question, simply named, acts as if he is a worker aboard the Big Shell, the large decontamination facility created where a majority of Metal Gear Solid 2 takes place. The official Metal Gear Twitter account perked up a bit today when it began responding to and retweeting another account from a fictional character on board Metal Gear Solid 2's Big Shell.