Other mistake: When assembling the Zeo Megazord, Zeo Zord V is the last to join, forming the head and back of the Zeo Megazord. When it has connected, we see all 5 Rangers slide down simultaneously into the head of the Zeo Megazord. Where it is piloted from and where did they slide down? The head has only just joined, and the other 4 Zeo Zord forms the rest of the body - not enough time for them ALL to slide up, and then back down again.
Continuity mistake: When the Gold Ranger calls upon his Golden Power Staff - first, his hand is at the top of the handle, right below the emblem. In the next shot, his hand is at the bottom of the handle, away from the emblem - there isn't enough time for his hand to drop.
Factual error: The climax of the episode features the Aquitain and Zeo Rangers fighting together, in Angel Grove. However, they are actually fighting outside the Tokyo Dome, in Japan. Further proof: http://www.rangergallery.com/albums/userpics/10012/Zeo%2520Rangers%2520and%2520Alien%2520Rangers.jpg.
Continuity mistake: At the start of the episode, Adam rolls behind a metal structure, knocking into some hanging chained levels, which caused them to sway quite violently. In the next shot, which is behind Adam, and levers are now stationary - it would take much longer than a fraction of a second for a lever to stop swinging.