Jacob Gehman’s review published on Letterboxd:
Avatar is fine. Edit it to down to an hour and forty-five minutes, and it'd have enough story to be interesting. However, it's two hours and forty-some minutes, giving it approximately an hour's worth of surplus.
This extra hour could have been used for good--they could have used it to build characters, relationships, conflict. But they didn't. So instead Avatar is a behemoth almost-three-hours long movie with a so-so storyline, cardboard characters, and made-for-tv relationships.
Objectively, Avatar is a bad movie.
What I feel like the producers of Avatar were banking on is the special effects dazzling audiences. Which perhaps explains this extra hour of nothing within Avatar's runtime. It just feels like one, long tech demo, while the boundaries of mid-to-late 2000's CGI is taken to the breaking point.
Avatar is a movie that is, in many ways, utterly beautiful on screen. The best moments are those where the characters step back and the camera just swoops through the alien world, taking in the strange foliage, the odd animals, the sparkles and breaths that have been created to give the world its shimmer.
And I, for as much as I want to lean on my critical druthers, am dazzled by the beauty.
But beauty is no replacement for narrative. Beauty can't create characters. Beauty doesn't build relationships. Beauty doesn't cause conflict. These are all things that take development within the narrative. And here they're just splashed on the screen without much thought. It's like they followed a checklist of when things happen in a movie and wanted the audience to just accept that.
The sad thing is that, even though Avatar is only six years old at this point, it still feels like it was made a few years too early. The animation of the alien bodies are a bit stiff and flat-looking. Considering the leaps forward that animation has been taking over the last few years, even waiting several would have given the filmmakers the tools needed to get them looking much better.
But while that's a strike against Avatar, the real problems are those mentioned about the narrative. And the length. The length compounds the narrative problems, and the narrative compounds the length problems.
Avatar is worth watching if you want a tech demo and have a whole lot of time to burn.