Chimera was a total conversion for the Myth II engine made by community members. It turned out so well, it got included in distributions of the Myth Codex.

GelospingmangoMan has Myth walkthroughs, with and without commentary, for the campaign scenarios of Myth 1, Myth 2, and Chimera.

Myth: The Fallen Lords w/o commentary
http://www.youtube.com/playlist?list=PLF5E232DFE2FEE606

Myth 2: Soulblighter w/o commentary
http://www.youtube.com/playlist?list=PL60385DC2CD63054A

Myth 2: Soulblighter
http://www.youtube.com/playlist?list=PL781F70A8A2244656

Myth 2: Chimera w/o commentary
http://www.youtube.com/playlist?list=PL9E41DE0B22A7406A