Turtle Rock Studios

Back near the turn of the century, a young upstart decided to form a small group of like minded folk who are passionate about creating fun and sensational video games. This fella liked where he hailed from and figured that naming the studio after his home was a grand idea.
And thus, Turtle Rock Studios was born.

The group came together and worked with Valve on some great content
for the Counter-Strike universe, including Counter-Strike: Condition
Zero and Counter-Strike: Source. The team then went on to
work with Valve on the hit game for the PC and
Xbox 360, "Left 4 Dead".

To this day, Turtle Rock Studios continues making new and exciting games. We reckon
you should swing back by the site now and then to see what they're up to. You never
know what they'll come up with next.

Source: The Publisher Website.