1. Summary
2. Background
3. Hype

Portal was, to the general public, an out-of-nowhere hit that spawned countless tired memes (you can stop saying "The cake is a lie" now) and intriguing gameplay. The portal gun has even been modded into other Valve titles, such as Team Fortress 2 and Half-Life 2. However, for three years nobody heard anything about Portal 2. With its glorious return via impressive trailer, you will have to tie us to a post to keep us from talking about it. After all, who doesn't want to return the wry, sardonic world of Portal?

Portal's most obvious influence is the game Narbacular Drop. Created by students at the DigiPen Institute of Technology, it's a freeware game revolving around the intelligent placement of portals inside of a living dungeon. Many of the elements in Narbacular Drop would make it over to portal, such as the demon antagonist (who is roughly equivalent to GLaDOS) and the portal-restricting surfaces. The reason why is simple: Valve hired the entire team that made Narbacular Drop and put them to work on Portal, which was to be an experimental game for the Orange Box. It turned out quite well, all things considered!

Portal also has a wry, dark, deadpan sense of humor about it. In nowhere else is this perfectly shown than through the character of GLaDOS. The two main writers for the game, Chet Faliszek and Erik Wolpaw, were both writers for the now-defunct gaming humor site Old Man Murray. Chet Faliszek also co-created the site Portal of Evil. With a penchant for the sarcastic and surreal, it's no wonder that the game is written the way it is. Players loved it, too, as it was one of the darkest and yet unrelentingly funny games in recent memory. It's also interesting to note how much of an influence Chet and Erik had on Half-Life before they went to work for Valve, as Gabe Newell claims them as an influence on the design of both the first and second games.

Portal could be compared to a rather famous short story titled "I Have No Mouth And I Must Scream." Written by Harlan Ellison, it depicts a future in which the last surviving humans are enslaved by an impossibly powerful supercomputer (named AM) which tortures them endlessly. This bears a stark and eerie resemblance to Portal, especially in relation to the maleficent and murderous GLaDOS and her lording over Chell. The sterile environment, purposeful deceptions, and realization that many have come before (and died in the process) only makes the connection even stronger.

Finally, Portal is obviously connected to the Half-Life 2 universe, and Valve applied the knowledge gained while working on their eminent series to Portal. There are references to the Aperture Science ship Borealis in Episode 2, and the ending of Portal depicts a world that looks much like the one in Half-Life 2. There are also subtler hints, such as the voice of Ellen McLain being in all three of the Orange Box games (GLaDOS, Combine Overwatch, Team Fortress Administrator) and the easter egg relating to Adrian Shepard on the Aperture Science keyboards. Despite Portal being an experimental game, it was made with all the know-how that Valve has, and it shows.