If it's been a while since you've heard anything of the STALKER series, that would be for good reason. Over the period of 2007 to 2009, STALKER began and ended with a series of three different games. The first game in the series, STALKER: Shadow of Chernobyl, released in 2007. A year later, STALKER: Clear Sky released as a prequel to Shadow of Chernobyl. It capped off with STALKER: Call of Pripyat in 2009, a direct continuation of the ending of the first game. It was really looking like we were going to get a healthy amount of STALKER games at that time, as the developers at GSC Game World announced a definitive sequel, STALKER 2, in 2010. In 2012, however, the sequel was canceled due to a disagreement with new investors. We haven't heard anything from the series since, until now. Sergiy Grygorovych, the CEO of GSC Game World, announced in a Facebook post that the sequel is in development, and is set for release in 2021.
The details were, rather coyly, left at that. In the post, he links folks to the official website for STALKER 2, which simply shows the logo and release date. No other information about it, like the story, gameplay, or platforms of release were given. Despite this, Sergiy seemed to hint on his Twitter that the game will be developed in Epic Games' Unreal Engine 4, due to a reply to another user and Sergiy's position as an employee at Epic. Anything else, like screenshots, artwork, or video are nowhere to be seen.
The STALKER series takes place in an alternate future version of Chernobyl; more specifically, the site of the infamous Chernobyl disaster, where an accidental mishap in their nuclear reactor caused large amounts of radiation to envelop the atmosphere surrounding the area. In the world of STALKER, a second explosion occurs at the plant, creating what's known as "The Zone". The Zone is filled with anomalies and treasures that are hunted down for personal gain by people known as STALKERS, who are divided up between solo hunters and factions. All three games have you playing as a different character, so it's quite possible that STALKER 2 will follow that same pattern.
The gameplay of the series is a unique blend of first-person shooter/survival horror mechanics, with some light RPG elements sprinkled throughout. Things like hunger, as well as your radiation level, must all be taken into account when traversing through its perilous world. If you've played the Metro series, it's similar to that, but with more mechanics involved. Things like branching dialogue and multiple endings also add to the replay value of the games, and just like with the differing-protagonist stories discussed above, these gameplay elements will likely see a revamping and return in STALKER 2.
So, needless to say, 2021 is quite far off, being a whole three years from now, and a whopping nine years after the projected release of the game back in the day. Since not much info was given at this time, it's unclear how far into development STALKER 2 actually is, or when we'll see more of it outside of this teaser. To help ease the wait for yourself in the meantime, though, a good idea would be to check out all three STALKER games and play them to get caught up. All three are available on PC only, via Steam or other digital distribution platforms. The first and third games will run you $19.99, while the second game is only $9.99. Coincidentally enough, this announcement times up with Metro Exodus' recent delay.