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Alien Swarm and Source-based SDK launching for free this Monday

In an announcement perhaps meant to obliterate the definition of "Valve Time," the publisher announced that Alien Swarm has been rebuilt in Source Engine and will be released -- for free, no less -- tomorrow, Monday, July 19. The team that originally built the mod for UT2004 has since been hired on by Valve for work on the Left 4 Dead series and Portal 2, but luckily found enough time to move their game over to Valve's game engine between bouts of working on those other two games.

If you're so inclined, you can pre-load Alien Swarm starting right now before it goes live tomorrow. Oh! And when it does go live, Valve will also release the full SDK for the game, allowing users to get a more thorough look at what makes the game tick. Us? We're just excited to blast swarms of aliens with the totally insane looking flamethrower seen above. Hit the break for a trailer of the game in action.

[Thanks, Morey]%Gallery-97701%

This article was originally published on Joystiq.