Escape Plan is a 2013 movie starring Sylvester Stallone and Arnold Schwarzenegger. Disregarding the "The Expendables" saga (which is just... utterly forgettable), this is (to my knowledge) the first time that these famous actors make a significant main role appearance in the same film, and it marks some kind of return to the big screen for Schwarzenegger. So it better be awesome!
However, while not utterly bad, the film was really meh.
The major problem I had with the film is that it promised something it didn't deliver. Both its title, and very prominently its prologue, and somewhat throughout the middle of the film, we were promised a "prison escape" film of the "heist movie" kind. In other words, a meticulously crafted plan to escape an "inescapable" prison, where the viewer is only given hints about the ultimate means of escape, and then during the final escape or after it, all the finer details are shown, and all the actions that were strange or obscure are explained to have had a concrete purpose, and how it all fits together. In fact, the prologue was exactly that, to the utmost detail.
In other words, the prologue kind of promises the viewer that the final escape will be even more intricate, even more suspenseful, even more contrived, even more full of surprises...
... and it didn't deliver. At all.
By the final act the genre of the movie changed from "heist movie" to just "mindless action." Yeah, they escape the prison, but there isn't even a hint of the intricacies promised in the prologue. (And this isn't even going into the ridiculous plot holes and technical inaccuracies.) This was a complete let-down, and it just outright ruined the movie.
In fact, I have noticed this trend to be more common in recent years: "Heist" movies, or such, that suddenly more or less change genres in the third act, where the original genre is completely shoved aside and they become just mindless action movies. I have seen several such movies in recent years.
I perfectly well understand that some scriptwriters want to avoid chiches. After all, we have already seen countless classical "heist" and "intricate prison escape" movies and TV series. Why not subvert the cliche and do something a bit different for a change?
That's nice and all, but not when you change the interesting premise to a boring action sequence. If you are going to change the premise, change it to something more interesting, not to something less interesting. Surprise the viewer, don't let them down. Make the viewers leave the theater with a sense of "I completely didn't expect that", rather than "meh, I was expecting an interesting third act, but all I got was just bullets and explosions all over the place."