We're making a note here, huge success
The Portal Companion Collection may be a compilation of two games that are over a decade old, but apparently there’s still some new content to be found! Dataminers have dug into the game to see what interesting tidbits they could find, and believe it or not, new content from Portal 2 was discovered.
The Portal Companion Collection hides Portal 2 beta levels in its source code, and this is the very first time this content has ever been seen. Somehow Valve has managed to keep all of the beta content for Portal 2 a secret up to now, but an oversight on the Portal Companion Collection has unlocked the vault.
The beta levels discovered match up with levels from the final game in some ways, but there’s definitely elements on display that were tweaked or removed all together. Along with that, dataminers have discovered an early version of the game’s ending, and access to the level shown in the game’s E3 reveal.
Finally, a massive co-op level has been dug up as well. This level showcases a lot of ideas that would eventually make it into the game’s multiplayer component.