>>212231657I was waiting for someone else to say it.
Good list:
Predator 1 & 2, and they should have continued to make them in an episodic format in different eras of history and places on Earth for a few more movies, or at least one anthology like the _Animatrix_.
Terminator 1 & 2. Terminator 1 was an excellent movie, and 2 established Judgement Day as a fixed event in human future history that we will eventually have to reconcile, as will be the case in real life. Terminator Salvation was the only good "sequel", even though it occurs somewhere in the timeline, and was what Terminator 3 & 4 should have been.
Aliens 1 & 2. The first to set up the second, the second to bring the action to a close and leave us with the open ending the franchise deserved. Prometheus was good, and chilling.
Garbage:
Any Predators crossovers with Aliens.
Terminator 3 and the "female supersoldier and drug addict beats terminators to death with her fists" and the "quirky role reversal" episode with the grey goo human replacement terminators, whatever those movies were called.
Aliens 3 & 4 were dogshit phone-it-in plots designed to rape the box office, but they're utter shit with the latest bigger bad as the primary protagonist. Romulus is teens-in-space, and therefore dogshit garbage.