There seems to be a contractual obligation that sequels need to be more expensive than their predecessors. With such trivial things like plot and character development fully established, the filmmakers often double down on scope, scale and spectacle, presumably because they operate under the impression that bigger always means better.
However, in an alarming majority of cases an increase in budget leads to a downturn in quality, as the filmmakers seem to think that bombarding audiences with money shots and massive-scale destruction is enough to distract them from the fact that things are sorely lacking in other areas.
Of course, not every sequel falls into the same trap, and box office returns would indicate that the approach definitely works, but sometimes they just get it so wrong that they forget everything that made the first installment such a success in the first place.
Throwing every penny of the budget up on the screen still can't cover up a bad movie, but based on how often it happens you'd be forgiven for thinking that the studios seem to believe that they can keep getting away with it.
10. Paranormal Activity 2
Although the very nature of the horror genre involves scaring people sh*tless, audiences nonetheless seemed more than happy to sit through 80 minutes of absolutely nothing and then a couple of jump scares right at the very end, which resulted in Paranormal Activity becoming one of the most profitable movies ever made after raking in $193m at the box office on a budget of just $15,000.
With those kind of profit margins, Blumhouse's decision to turn it into their next big franchise was an obvious one, but even by the time the second installment arrived a year later, the novelty had already worn off. $3m is a drop in the ocean compared to almost any other movie, but when you consider that it cost two hundred times more to produce than its predecessor, you would have expected them to at least put in a little more effort.
Instead, we basically get the exact same movie all over again, with large swathes of nothingness book-ended by frights you can see coming from a mile away, and it hardly came as a surprise that the critical and commercial reception was a lot more muted this time around.