I acted as VFX supervisor as well as artist. I worked with another artist on the 6K footage over the course of a few months. We did multiple matte paintings for backgrounds, especially where houses or civilization were shown (this was filmed in various parts of Utah), but I also did the following more ambitious effects, with the time they appear in the video:
Leaves (13:45): I tracked the shot in After Effects, and did the rest in Blender. It took ~10 hours to render, both in 3D and compositing.
Stars (from 3:51 to 4:45): I composited the stars using After Effects. Keying was used for the static shot, while the tilt shot used a simple tracked mask. The mountains were also added. Many thanks for the skymap on NASA's website: https://svs.gsfc.nasa.gov/3895
Gunshot (after 6:00): I used OpenGL smoke and simple spark particles in Blender. It only took an hour or two to render.