The third episode has been released for Halo 4: Forward Unto Dawn.
Halo 2: Anniversary - Cinematic Trailer
Take a first look at the overhauled Halo 2: Anniversary cut-scenes in this trailer from Blur Studio.
Halo 4 Spartan Ops - Episode 2
Here is the second CG episode created for Halo 4's Spartan Ops.
Making Halo 4 - Part 1 and 2
Join 343 Industries on a 20 minute behind the scenes featurette on the creation of Halo 4.