The elaborate campaign is headed by marketing firm employees Chris Salem and Kyle Mazzei, who say their firm — McKee Wallwork & Co. — is supporting their push to bring the game to life.

At the $3,000 tier, Salem and Mazzei will create a Google AdWord campaign targetting all 300 employees of Valve, which will read "we want Half-Life 3."

Once the $9,000 tier is reached, a truck with a giant billboard will "besiege" Valve headquarters in Washington with a similar message.

At the $45,000 tier, the pair will hire Gabe Newell look-a-likes to enter the Valve headquarters, all wearing "we want Half-Life 3" t-shirts.

Finally, at the $150,000 tier, a concert will be held in Seattle featuring "some of the biggest names in video game music" and invite Valve employees and fans.

You can check out a trailer for their campaign below: