Timesplitters 2 HD was once planned for release on XBL Arcade, and Killer Instinct HD was also in consideration, according to Free Radical.
Speaking with Not Enough Shaders, Free Radical and former Rare staff members Steve Ellis, Martin Wakeley and Lee Musgrave said TimeSplitters 2 HD was development at Free Radical in 2008.
"I don't know what happened to that but yes, I'd love to see it released at some point," said Ellis. "Maybe it could be the catalyst that is required in order to raise enough interest in TimeSplitters 4 that a publisher might want to fund it."
Lee Musgrave said TimeSplitters 2 HD was going to possibly be the first of several collaborations with third parties in which the team would breathe new life into old franchises.
"Rare outsourced some of the conversion/development of Banjo Kazooie for Xbox Live Arcade, and it was kind of a test case for us to see what could be achieved in terms of developing with a partner, keeping our costs low and making some revenue," he said. "You can make your own conclusions as to how that turned out by the fact that we didn't move on to any of the other games you mention.
"We came close to firing off a conversion of Killer Instinct a few times, but there were licensing obstacles to that, and it never really had enough perceived interest to push it forward."
Crytek recently told VG247 that it's been gauging the popularity of the Timesplitters franchise through the community, and while the "volume of responses" regarding a Timesplitters 4 is quite high, "it’s not high enough yet," said CEO Cevat Yerli.