Turtle Rock Studios’ concept has hit the internet.

After finishing development on CS:CZ or Counter-Strike: Condition Zero for Valve, Turtle Rock Studios had some ideas. One of them never got further than an idea (a first-person wizard game), and the other significantly impacted the gaming industry. They had an idea for a mod that transformed Counter-Strike’s counter-terrorists into bots that attacked in waves, fighting only with knives. It was Terror-Strike, Left 4 Dead’s basis.

In a commentary on Left 4 Dead, Michael Booth, founder of Turtle Rock Studios, explained: “While we were developing bots for Counter-Strike: Source, we discovered that a few of us armed to the teeth with automatic weaponry against 30 knife-wielding enemy bots was a lot of fun. After shipping Counter-Strike: Source in late 2004, we started experimenting with new game prototypes. That basic kernel of ‘small team of friends against hordes of clawing enemies’ was something we kept coming back to, and we soon realized that the ‘co-op vs the horde game’ had a ton of potential.”

The types of opponents and the dialog between characters weren’t worked out until later, but the prototype for Terror-Strike shows that Booth wasn’t kidding. There is enormous potential in the gameplay because it can be fun to wipe out those who can’t shoot back at you in the game, and it can be exciting when you have to back up in a hallway to reload your weapon while they’re coming at you in droves. The prototype leak is just a tiny snippet of the Counter-Strike maps that have been leaked onto the internet!

Zombie-City, available on GameBana, could be the original concept that Turtle Rock Studios showed Valve. It might be a slightly later version, though. A modder, Wolfcl0ck, modified a few things to make it playable (new material, an overview texture, a new mesh, a map description, and all packed into the bsp for convenience). Consider that the studio’s later games, Evolve and Back 4 Blood, would not have been made without it.

Source: PCGamer