Mega developer Valve has launched a public beta for online shooter Team Fortress 2 over three years after its release.
Why? To test "new technologies without the risk of breaking the game", the developer wrote on the Team Fortress 2 blog.
Valve's testing class, item and weapon changes. Mysterious "higher level, game-wide experiments" are going on, too.
And as with all betas, the developer wants your feedback.
"As you've probably seen by now, we like to change things in Team Fortress 2," Valve said. "A lot. And while we're perfect most of the time, we occasionally get something wrong. One reason for this is we just don't get enough data from internal play testing, and another is that we spend too much time watching Tom Bui serenades on YouTube."
The beta is open to all who own the game. To install, launch Steam, open the Library and install "Team Fortress 2 Beta" from your games list.
Tom turned up a 9/10 in Eurogamer's 2007 Team Fortress 2 review. The game was bundled with Portal, Half-Life 2, Episode One and Episode Two in stunning compilation The Orange Box.