But even though we're mere weeks away from the game's launch, we've still yet to get any concrete details on how it all works.

That's changed today, as the mega-developer has given some more specific details on Portal 2's Steam integration. The PS3 version of the game will feature a Steam overlay, providing access to both your PSN and Steam friends. The overlay will display their in-game and online status, as well as providing portals for text chat, player profiles and more.

You'll earn Steam achievements alongside PS3 trophies, and both will be viewable from the Steam overlay.

The game will be Steam Cloud-enabled, and will save both co-op and single player progress online, meaning you can pick up progress from where-ever you left off on any console. Assuming you're logged in of course.

To access all of the features, you'll obviously need to have a Steam account and link it to your PSN profile. New copies of the PS3 game will also come with an unlock code for a PC copy of the game.

Phew. Incredible. Valve don't do things by half, do they?