Mark Adler’s review published on Letterboxd:
War Horse is pretty okay when it's about the war but pretty not so good when it's about the horse. The first 30–40 minutes are honestly unbearable and are written like a Disney channel original feature, with shot composition that's not too impressive either. They're a slog of gray and brown mediums. I guess the crew really felt like that horse needed some character development for some reason. After the titular war makes the horse a war horse, the movie takes a turn for the better with a few solid moments sprinkled in there. The production values are great; I never questioned the aesthetic of the time period and there wasn't an overreliance on CGI. I liked the variation in how deaths are depicted and how there were actual stakes to characters' involvement in the war. No one act plays out for more than 40 minutes so you can't really get bored for too long either. If this film cut down on the cheese, played out more as an anthology, had cinematography that was less insistently gloomy, and had a 2-hour runtime then it probably could've been great. As it exists, though War Horse is a solid war film buried under a mediocre horse film.