Valve designer Robin Walker has revealed that Episode Two is already in development and that Episode One will leave gamers on tenterhooks.

Having recently been informed of the episodic nature of future Half-Life 2 expansions, it will come as no surprise to learn that, with Episode One only a few months away, Episode Two is already well into production. Speaking with CVG, Robin Walker said that the second episode "has been in development for some time." He did not, however, give an indication of when we can expect it to be released.

Speaking about Episode One, Walker revealed that as was the case with Half-Life 2, the expansion "will not end with an all-encompassing conclusion," which is a sure-fire way to ensure gamers are compelled to purchase Episode Two. Episode One won't be all tease though, with a promise of answers to several questions left unanswered in Half-Life 2.