Just in time for the release of Half-Life: Alyx in March, Valve is offering gamers a chance to play the original Half-Life games on Steam for the next two months.

The list of free-to-play games includes the original Half-Life, Half-Life 2 and both expansions – Half-Life 2: Episode One and Half-Life 2: Episode Two.

The only caveats here are the fact that you play the games through Steam – which, for most folks, isn’t a big deal – and they're only free for two months. Once Half-Life: Alyx comes out in March, all the games will go back to their original price.

Click the links below to play the games for free:

Travel backwards (and forwards) in time with Gordon Freeman

So, why is Valve being so generous? Primarily to drum up interest for Half-Life: Alyx - its new VR game set before the events of Half-Life 2 and both Episodes.

“Half-Life: Alyx is set before the events of Half-Life 2 and the episodes, but the games share characters and story elements,” Valve said in a news post . “The Half-Life: Alyx team believes that the best way to enjoy the new game is to play through the old ones, especially Half-Life 2 and the episodes, so we want to make that as easy as possible.”

If you just want to play the latest game in the series, Half-Life: Alyx is due out in March and will be available for free with every Valve Index VR headset.