The two games are SiN Episode 1: Emergence and Half-Life 2: Episode One . Both will be familiar to most FPS gamers, SiN being a continuation of the older game SiN, and Half-Life 2 being an add-on for, well, we forget the game it was based on. Either way, the story here is not so much the releases as the paradigm shift they represent.

Both games have the tag "Episode 1:", and this is significant because Valve has stated it is aiming for shorter, cheaper, episodic games, much like a TV series instead of a big-budget movie.

SiN will be selling on Steam for US$19.95 -- about 40% the price of a modern game. It is available for pre-load now, and will be ready to play on May 9. Meanwhile, the highly anticipated Half-Life 2: Episode One goes live on June 1, 2006.

The catch is they will be much shorter than a full blown epic like HL2, with the HL2 episode coming in at a claimed 4-6 hours of gameplay, SiN at 3-6. This is about half the time of a 'normal' game for less than half the price, a good value, but will it fly with the people spending the money?

That is the question, and that is the new idea that Valve is floating -- cheaper, quicker and very different. Because of the Steam system, Valve can offer smaller chunks without the overhead of retail, and probably make a lot of money doing it.

Valve's Steam distribution program was the subject of ongoing court disputes between Valve and their publisher Vivendi Universal Games (VUG) when the original Half Life 2 was made available online.

Will people tune into Steam every so often for the latest episode? If so, Valve can fundamentally change how gaming is done, and that may be a very good thing. Or it may be a very bad thing.