SiN Episodes 2
SiN Episodes 2 was to be the next episode in the SiN Episodes series, following on from SiN Episodes: Emergence. Presumably development began immediately after the release of SiN Episodes: Emergence but the acquisition of Ritual Entertainment by casual game developers MumboJumbo on 24th January 2007 seems to have been the end of any development as MumboJumbo only appeared interested in the development of casual games (Stokker, http://www.playfuls.com/news_9082_Ritual_Entertainment_Acquired_By_Casual_Games_Developer.html).
According to Michael Russell, no subtitle had been decided but the story had been established and two new weapons and five maps had been designed, though no media was ever released.
It is unlikely that SiN Episodes 2 will be completed at this point: MumboJumbo no longer appears to exists and while NightDive Studios acquired the rights to SiN, it is unclear if they also acquired the rights to SiN Episodes: Emergence or SiN Episodes 2 as well.