Also, birds don't generate lift from merely flapping their wings up and down, they generate lift due to the angle of attack of the wing during the upstroke and downstroke. The wings in this video don't address this issue.
Depends on the bird and mode of flight. Large birds like condors basically glide like fixed-wing aircraft, flapping every few minutes; hummingbirds flap at 200 Hz and use various aerodynamic tricks to stay aloft. The flight in the video looks similar to the that of those toy flapping birds powered by a rubber band. It's possible to flap & fly without fully articulated twisting wings, just not as efficient.
True, however those toy birds generate forward thrust and rely on the tail to move upwards or downwards since they're so simplistic. There is no tail on the device in the video, so there's no mechanism driving it upward.
