The movies are so simple they could be considered genius (could is the key word here). A group of people avoid a catastrophic event and then slowly get killed in super creative Rube Goldberg devil schemes.
Imagine if someone got blown up at the end of that, and you'd have a general idea of what's going down this series. The thrill of the series lies in the execution of these set-ups, the knowledge that everyone knows what's coming, and that it can't be stopped. For that reason, the films must be viewed in a packed theatre to do them justice. So if you are even remotely interested, you owe it yourself for one FINAL movie of the summer.
** With this being the last movie of the summer, you can expect a Summer movie wrap up on Monday.