These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Darkhorse: Lado. Even most people who didn't like the movie itself have highly praised Benicio Del Toro's performance as the monstrous, but so very entertaining psychopath, labelling him as arguably being THE most interesting and engaging character. Elena and Dennis have gotten a decent amount of praise too, even if it hasn't been nearly as unanimous as with Lado.
Moral Event Horizon: It's tough to pin down when exactly Lado crosses it. Perhaps it's when he orders Esteban to murder a woman generally unassociated with the previous cartel. Or threatens to kill Dennis' children. Or kills Esteban for being "too soft." Or when he rapes O.
Poison Oak Epileptic Trees: The theory that the Imagine Spot first ending is completely true. O secretly cared for Lado so she created a happy ending where he won and both Chon and Ben lived.
The Scrappy: The protagonists have all gotten at least a little bit of flack, but O easily gets the most among most people for various reasons. Some have complained that her narrative segments are grating, if not unbearable, others think that she's too bland and one-dimensional to be the character that drives the plot and connects all of the others, and there are some who can't stand her annoying demands for getting better food and accomodations from her kidnappers when she should feel grateful to even be alive in the first place (this is the Mexican Drug Cartel after all, not a group that's well-known for their hospitality).