Some of my readers might not want to see the actual crash. If you want to analyze the accident the following is a side view.
Snap rolling a propeller powered aircraft uses the torque of the engine to roll the aircraft at high angle of attack. You yank on a pull and the engine rolls the aircraft on its back to the left. Simultaneously the pilot eases right rudder and the aircraft rolls with a snap, thus the name Snap Roll. It appears to me the pilot entered the maneuver slow which necessitated a lot of right rudder. The low speed probably also contributed to the nose not getting high enough before the roll completed (frame 32). The pilot then augmented the roll with aileron (rolling left) in an attempt to get the aircraft fully inverted. It never did make it fully inverted. As you can see in the AP still photo above, the velocity vector (where the aircraft was going) was down. Descending and slow he had to push in an attempt to hold altitude. The flight controls were still crossed (right rudder/left aileron) his push raised the angle of attack on the wing and it then stalled. No doubt weight and aerodynamics of the Wing Walker caused the wing she was on to stall first. It begins a wing drop at approximately frame 35, too low to effect recovery.
Below is a link to a nose on view. In it you can see how the aircraft mushes into the maneuver (a condition of not enough airspeed). Very sad.