The Return of Wonder Woman - S2-E1
Continuity mistake: Quite a few of the exterior shots of the jet which Steve is on are flipped shots (including the landing closeup), note the tail number "N207L" is backwards.
The Man Who Could Move the World - S2-E3
Continuity mistake: Steve complains that he can't steer the Jeep. The Japanese doctor is using mind control to keep Steve from being able to control the Jeep. However, in several shots, Steve can easily be seen steering the Jeep despite the doctor's continued control over it.
The Bermuda Triangle Crisis - S2-E4
Continuity mistake: Steve and Diana steal wrinkled uniforms from a clothesline. However when they put the uniforms on, they're perfectly pressed.
The Bermuda Triangle Crisis - S2-E4
Continuity mistake: After Wonder Woman gets Steve out of the tree, you can see a big shrub in the foreground on the right side of Steve's body. When the camera changes angles, the shrub is suddenly gone.
The Bermuda Triangle Crisis - S2-E4
Continuity mistake: Steve's parachute moves around, even though it's flat on the ground and no one moved it. After Wonder Woman rescues Steve from the tree, Steve is laying on the ground motionless and unconscious. His parachute moves around between the time Wonder Woman walks away and Diana returns, even though nothing could have moved it. It wouldn't be so obvious, except that the material is red and white, so when it changes, you can really tell.
Continuity mistake: When Diana escapes from the guy who had kidnapped the boy, she runs into the woods wearing a dress. When she starts to turn into Wonder Woman, she is somehow now wearing pants just before she changes into Wonder Woman.
I Do, I Do - S2-E8
Continuity mistake: When Wonder Woman is chasing the golf cart, in the close-ups, the golf bags are not moving, but in the far-away shot, one golf bag is bouncing all over the place. When they zoom in, it's not moving again.
Mind Stealers from Outer Space: Part 1 - S2-E10
Continuity mistake: The doctor's arms change positions, and holds a stethoscope that disappears and reappears as he speaks with Diana Prince.
Continuity mistake: Diana spins herself into Wonder Woman before she enters the gym. Watch the trash can behind her - it suddenly disappears. Additionally, in the widescreen version, a security guard can be seen standing between the car and metal door, though surely Diana would not transform into Wonder Woman in right front of someone (the guard is not visible in the original fullscreen version). (00:35:45)
Continuity mistake: When Mariposa is skydiving out of the plane, any time he's seen from afar, he's wearing a black oxygen mask. When the camera is closer to Mariposa, he's not wearing a mask. However, when he lands, he is wearing a mask.
Continuity mistake: Wonder Woman jumps through a window, and all of the glass smashes out, everywhere. In following shots there is no glass on the floor or the surrounding area.
Continuity mistake: When Wonder Woman tries to escape from the building, she's in the room with the padded floor and walls. Her heels are missing from her Wonder Woman boots, but they were on when she was in the hallway.
Continuity mistake: When Steve lands his plane, all you can see in the background is what looks like a wide open desert. However, when he comes to a stop, the jet is now in the middle of a completely different background and there was not sufficient time for it to go from the desert to this location in such a short distance.
Answer: The transformation twirling was invented for the 1970s TV series only, to explain her quick change from Diana Prince to Wonder Woman. However, it would have been nice to do a little spin homage in the movie.