Transformers: The Movie (1986)

Continuity: In the battle scene at autobot city, Megatron orders Soundwave to jam the transmission that Blaster is sending to Optimus Prime. When Soundwave ejects Rumble, Frenzy, Ravage & Ratbat we see them flying through the air transforming simultaneously and and both Rumble & Frenzy are coloured the same (red & black) when Rumble is supposed to be purple.

Continuity: During their fight at Autobot city, Megatron throws a rock at Optimus like a spear. Before he throws it it, looks big in his hands, but when it hits Optimus it looks quite smaller and fatter. Then Optimus pulls it out and it's back to the right size again.

Continuity: Towards the end of the movie, Spike and a few autobots are about to be dropped into the vat of acid. When the view is from above the vat, look carefully to see Daniel already in the room standing in the very spot he will shoot the cover from. However, a frame or two later shows Daniel running into the room.

Even though Starscream was killed in the movie, he came back in 2 later TV episodes as a ghost. He also appeared in 1 Beast Wars episode.

The creatures that judge Kranix, Hot Rod and Kup are later revealed in the next series of the Transformers cartoon to be the creators of all Transformers, and used to be the masters of them and Cybertron millions of years a go. They are called Quintessons.

It seems Huffer dies in the movie, but you don't see this character get killed. The evidence is that in the episode "Dark Awakening" the Autobots find a graveyard ship with a lot of the killed of characters bodies inside, and one grave says Huffer on it.