The Terminator could have ended differently. In particular, the fight against the first machine didn't have to be over right then and there. And if the machine had somehow survived, that would have made it easier to devise sequels, since it wouldn't have required any monkeying with the timeline. The quality of the three sequels that followed suggest that perhaps a different path would have been better for the long-term health of the franchise.
So, what might have happened? I'm thinking the point of departure is when Sarah and Kyle flee into the factory from the T-800. Kyle tries to fight it with something like a big drill, but is knocked aside, hurt and out of the fight. Sarah manages to trick it into some sort of industrial machinery that cuts it off at the thighs. It continues pursuit, dragging itself along on its hands, but Sarah and Kyle are now much faster and are able to escape into a car and drive off. The final scenes have Sarah driving a car along a dark highway with Kyle lying in the back seat, and the T-800 returning to the factory floor to pick up its cut-off legs.
Given this revised ending, what should the next film in the series look like?