Valve Accidentally Released an Early Left 4 Dead Prototype in an Update for Counter-Strike

Valve accidentally released an “extremely early” Left 4 Dead prototype in Counter-Strike’s new 1.6 update.

As reported by Eurogamer, Gabe Follower shared that this prototype – which is called Terror Strike – was “accidentally compiled” and came packaged with the latest update. It’s a fascinating look at how Left 4 Dead’s origins can be seen in a mod for Counter-Strike: Condition Zero and were built with Counter-Strike assets.

Valve accidentally compiled and pushed earliest Left 4 Dead prototype called “Terror Strike” into the latest CS 1.6 update and community figured out how to play it. pic.twitter.com/llVkYCip69

— ‎Gabe Follower (@gabefollower) November 23, 2023

The files for the prototype were quickly pulled offline by Valve, but, as the internet is known to do, it quickly downloaded them and reuploaded them for the public to use.

Gabe Follower shared a few more details about Terror Strike, saying, “User under name ‘The One Epicplayer’ ported zombie_city map and did the bot navigation mesh. @pDylan002 sent me the info.”

“The terrorist with the bomb must make it to the house and plant the bomb. Zombies will respawn a little bit after being killed,” Gabe Follower continued. “Once the bomb is planted, every zombie will respawn and a horde will come for the survivors. The survivors must survive the horde by killing all the zombies. The round is won when all zombies are killed while the bomb is planted.”

For more, check out more gameplay of Terror Strike from YouTuber ilovethevopo and our look at how you can get into Counter-Strike 2 in 2023.

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Adam Bankhurst is a news writer for IGN. You can follow him on Twitter @AdamBankhurst and on Twitch.