Counter-Strike update accidentally includes a prototype of Left 4 Dead

For the 25th anniversary of Half-Life, Valve has updated Counter-Strike 1.6, but also seemingly released an early version of Left 4 Dead.

Counter-Strike Left 4 Dead prototype: A soldier in tactical gear from Valve FPS game Counter-Strike

A new Counter-Strike update contains an extremely early prototype of zombie co-op shooter Left 4 Dead. To celebrate the 25th anniversary of Half-Life, Valve has released a variety of new material for its epochal, single-player FPS. The developer has also updated the legendary Counter-Strike 1.6, in order to make it compatible with changes in Half-Life itself. However, in the process of updating CS 1.6, it appears Valve has accidentally included a prototype of L4D that was built as a mod for Counter-Strike Condition Zero. If you want a change from Counter-Strike 2, here’s something very different indeed.

Counter-Strike 2 is obviously the latest version of Valve’s tentpole FPS game, but there have been several iterations, including Counter-Strike Source, CSGO, Counter-Strike Condition Zero, and good old CS 1.6. In the past, fans unearthed a map called ‘Zombie City’ which appeared to be a prototype location for Left 4 Dead, built for Condition Zero. Remember, Left 4 Dead was originally being created by Turtle Rock, which was eventually bought by Valve for the launch of L4D itself. Turtle Rock created the earliest versions of Left 4 Dead as Counter-Strike mods – Zombie City was one of the remnants of those early prototypes.

And now, it seems we have found another. With the original Half-Life updated for the 25th anniversary, Valve has also updated CS 1.6, since it was originally a mod for Half-Life and shares some of the same functionality. However, one of the new updates for CS 1.6, released on Wednesday November 22, included code for one of Turtle Rock’s Left 4 Dead prototypes. The prototype itself was actually made for Counter-Strike Condition Zero, but since that game shares some code with 1.6, the L4D prototype has somehow snuck into this update.

Dubbed ‘Terror-Strike,’ fans have already managed to take these files and make them work in Condition Zero itself. Combining the Terror-Strike code with the leaked Zombie City map from earlier in 2023 provides a more complete picture of the earliest versions of Left 4 Dead. You can see more in a video shared by YouTuber ‘ilovethevopo.’

YouTube Thumbnail

It comes as one former Left 4 Dead developer says the game was “broken” at launch. Meanwhile, Valve has also fixed a 25-year-old Half-Life bug.

Grab the best CS2 crosshairs right now, if you want to up your game. You can also get the best CS2 binds to help you play like a pro.

Also, make sure to follow us on Google News for daily PC gaming news, guides, and reviews.