10 Ways Video Games Blew Your Mind (Without You Even Realising)

Remember the distant utopia of 2008? Remember playing Left 4 Dead split screen on a tiny telly and being blown away not only by the sheer amount of zombies on screen but also by how much replay value there was in just those 4 short campaigns? Well, that's because Valve put a massive amount of effort into a radical new AI system which has barely been matched to this day.

Beyond the AI of the zombie hordes and special monsters is the unseen and ominously titled "AI Director", a dynamic system that alters the game's pacing, difficulty and atmosphere on the fly.

Depending on players' statuses and skills during the playthrough, the director controls when and where hordes will spawn and how frequently players encounter pickups such as ammo and health, creating a different experience every time the game is played.

Left 4 Dead 2 introduced The AI Director 2.0, which expanded on this massively. The director was now able to alter the layout of levels to avoid the player simply rushing to the end, and would reward players with better items should they take more difficult routes.

It seems that every now and then when the stars align and Valve actually release a game, it'll be vastly ahead of the curve.