Codename: Gordon
Codename: Gordon, also known as Half-Life 2D, is a two-dimensional Flash sidescroller game by Paul "X-Tender" Kamma and Sönke "Warbeast" Seidel. The game was produced on behalf of Nuclear Vision and distributed for free via Valve Software's online distribution system Steam as a promotional title for the then upcoming Half-Life 2. The game has since been removed from the Steam store due to the developer's bankruptcy. The game began as a fan project by Paul Kamma and Sönke Seidel, whose concept was inspired by various Half-Life 2 commercials. Soon after, the two began working on Codename: Gordon on behalf of Nuclear Vision. The company also presented the game to Valve, the development team of the original Half-Life series, which later distributed the game via Steam.
Story
Codename: Gordon presents an alternative to the Half-Life 2 storyline, with locations inspired by both Half-Life and Half-Life 2. Along the way, Gordon Freeman - the protagonist from the canon games - meets some of the main characters from the Half-Life series and tries to find out what caused the disappearance of the third dimension. The game starts with Gordon Freeman in a port area. After making his way through some zombies and headcrabs, Gordon meets Barney Calhoun, an important character in the later Half-Life titles. He tells Gordon about an "entire dimension" that has disappeared, and points out that the science team is working to solve the problem. Since Barney is injured, he can't leave the place, so he gives Gordon his gun and tells him to leave without him. In the second chapter, the player encounters Eli Vance and his daughter Alyx, who tell Gordon to take their car, which he can use to reach Town 17, since it seems to be the center of the problem. They also advise him to talk to Dr. Kleiner about his new invention, the gravity gun. Shortly after, the player meets Dr. Kleiner, who tells Gordon about his worries about the missing dimension and also gives him the gravity gun mentioned by Eli and Alyx. After being attacked by an alien battleship and passing a prison heavily guarded by Combine soldiers, Gordon reaches City 17 where he finds the G-Man. He tells the player that he has been expecting him and claims that he is not behind the disappearing dimension thing, but is just a "lowly pawn in a dark game played by sinister forces." Shortly thereafter, Gordon encounters a Strider - a large three-legged attack unit - which turns out to be the cause of the problem, as a portal opens after he defeats it.