PC players are getting a big STFU from Steam. That's right, Super Time Force Ultra is coming to Steam and is getting some bonus characters from Valve.

In order to celebrate the launch of Super Time Force Ultra on Steam this week, Capybara Games is adding characters from Left 4 Dead and Team Fortress 2 into its pixelated, punishing shooter. The first new addition is Pyro from Team Fortress 2. Pyro has his trademark flare gun and flamethrower to help decimate the enemy forces. Zoey from Left 4 Dead has her twin handguns and can throw propane tanks, resulting in some nice explosions.

The last new character is Saxton Hale from Team Fortress 2. Saxton is all muscle, straight to business and doesn't have any guns. That's right, he's in a side-scrolling shooter without a weapon, but his fists and speed are so deadly that he's not at a disadvantage.

Super time Force Ultra will be launching on Steam on Aug. 25.