The first frame shows a background sky highly distorted by the black hole in the center. The gravity of the black hole is so great that it actually deflects the background starlight. Large light bending effects cause the background sky to appear to move in unusual ways as you circle the black hole. Light paths are so curved that light can reach you from anywhere on the sky - even from behind the black hole - no part of the sky is eclipsed. Distant starlight has fallen to you and therefore appears 'blueshifted.'
The large light bending effects cause stars on the opposite side of the black hole to become greatly magnified. Stars usually too dim to see become visible. If you watch closely you can identify an invisible circular ring around the black hole on either side of which stars counter-rotate. This is an Einstein ring , and stars do not cross through it. Stars approaching the exact opposite side of the black hole from you are seen to have two bright images, one appearing just outside this Einstein ring, and the other 180 degrees around the face of the black hole and just inside this Einstein ring. Stars in this location appear to move with the highest angular speed.
Next: Dropping down to the photon sphere.