Continuity mistake: When Ash and friends are going into an alley, Ash's collar changes from white, to blue, to cream, and back to blue. Also, his face changes from skin colour to white. (00:10:27)
Continuity mistake: When Oswald begins testing the joystick, there is a button that is green, but in the next shot, it is blue. (00:16:10)
Revealing mistake: As the camera pans up to Meowth in a crane, a building's windows move with the screen. (00:08:01)
Answer: He is a good guy but just found himself in a bad situation when he worked for Lysander. He didn't want him to harm Ash and his Pokémon when he was trying to get the special bond between Ash and his Greninja to work. He does leave Lysander and go back to being a good person.