Some sequels are merely terrible. Other sequels are so awful, their name should not be spoken because their mere existence makes the rest of the franchise look bad.
When is the last time, for instance, that you had a meaningful conversation about Beverly Hills Cop III? What’s that? You didn’t even know there was a Beverly Hills Cop III? That’s because nobody ever talks about it.
It is easy to note that I watched three Lethal Weapon films when there are, in fact, four. The first three films are an exercise in increasing laziness that manages to be entertaining anway. Every one of them involves Murtaugh and Riggs stumbling across a major drug ring and bringing it down while Murtaugh continues to insist he is too old for this shit.
They add a new character in each film and if the character is successful, they add more in the next one. Joe Pesci is around just enough to be interesting in Lethal Weapon II, they give him a bigger role in Lethal Weapon III. Then they mix Renee Russo into the story in Lethal Weapon III.
And then comes the moment when they make the fatal decision to make Lethal Weapon IV and the whole thing goes to hell.