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.
Contested Sequel: It's often debated whether the second and third movies were worthy additions, or if it would have been best to let the first movie stand on its own. Even people who believe the first film to be far superior can't agree on whether Cube 2: Hypercube or Cube Zero was the better sequel.
Cube 2: Hypercube might have retained the mystery of the Cube, was more serious but far less gory, and had a unique look, but still had some silly characters and Narm scenes. (Sean Hood's original proposal script for Hypercube was on par with Natali's original; better characters, consistently darker mood as the plot goes on and actual, constant danger.)
Cube Zero visually retained the industrial look of the first film and was far less serious with more humorous scenes than either previous film, and left little to no mystery at all, but heightened the gore in places and at least attempted continuity with the first film.
Moral Event Horizon: Quentin grows steadily more hostile over the course of the film, but he doesn't make the full transition into becoming a genuine threat to the group until he kills Holloway by letting her fall to her death. It's not very surprising that our protagonists eventually try to get rid of him afterwards.