That movie didn't switch gears, it switched genres. That film is ridiculous in how it suddenly and awkwardly becomes a slasher film midway (or 3/4's of the way) through.

I was digging it and suddenly was just staring at the screen like "What just happened? Did somebody turn the channel or something?" It's almost like they showed up on set with the second half of a different script and were like "Fuck it, let's see if it works"