SiN Episodes

Planned as an episodic sequel to SiN, set 4 years after the end of the game, only 1 of the planned 9 episodes were released.
The episodes were going to be playable in any order with independent story segments, planned playtime of 4-6 hours, with an overarching story.

Initially aiming for a development cycle of 4-6 months between releases, there was plans for changing future episodes depending on what players did in the previous ones. To do this, specific gameplay data was recorded and could be uploaded anonymously by players at any time.
This information included gameplay options like the difficulty level, assistance level and use of cheats as well as stats like weapon specific kills, deaths per map, secrets found, completion time and highscores for those playing on Hardcorps mode.

"SiN Episodes: Emergence launches the new era of episodic gaming. A first person shooter powered by Valve's award-winning Source technology, SiN Episodes offers unprecedented interactivity, an engrossing story, and a revolutionary dynamic difficulty system that provides a custom experience based on your skill level and play style."