The first Jurassic Park movie is all time one of the greatest films ever made with the special effects still holding up to this day. The 2nd film was still very enjoyable in my opinion but it was just a cookie cutter sequel not bad, not good. The 3rd film wasn’t great at all. But compared to the rest of the series the 3rd film is basically the godfather.
As another personal pick the 1st blade movie is a hood classic good. The other 2 not so much.
Pretty much all of them. Successful first movie, sequels that repeat the formula while entirely missing the point.
Aliens.
Was one of the few exceptions to this for a long time.
I agree, there are a few sequels I liked on their own merits. But the majority of the ones are just as you said.
That said, I have a weakness for space ship drama. Can’t be too much of that. So some sequels really don’t need much of a plot, rhyme or reason. I’ll spend my money on them.