More organic to the conflict creation is Koba (Christopher Gordon in the prior film, Toby Kebbell here), the aforementioned psycho John McCain chimp who, while deferential to Caesar on the surface, sees his commander-in-chief as a weak appeaser who simply doesn't get that humans are an evil foe to be conquered. Though it's hard to tell under the digital makeover, Kebbell's voice inspires confidence that he will make a decent Dr. Doom in the upcoming Fantastic Four reboot (ironically, Gordon was Chris Evans' stunt double in the previous iteration), so at least they got one casting choice right. Koba is the closest thing to a villain the film has, and his scarred visage makes him suitably frightening, though maybe he could commiserate with Simba's uncle about the role facially injured animals are so often forced into onscreen.
Planet of the Apes movies traditionally end not only unhappily, but also with a message that the cycle of war will continue anew - key to the "anew" part, though, is that the subsequent film usually adds a different element to the conflict. This is essentially the same conflict as before, but continued, and unended, despite a crowd-pleasing climactic fight. It still feels like a prequel to something rather than the main event - as with The Phantom Menace, you get the sense that every significant plot point could be taken care of in five minutes to save us a movie. And of course, it IS a prequel: the filmmakers are saying this all leads to the Charlton Heston film, and if you wonder how that could be, use JJ Abrams logic and imagine Cornelius and Zira enter a tangent-universe past in Escape From the Planet of the Apes, resetting events anew. (Am I the only one who now wants to see the prequel about those face-peeling, nuke-worshipping mutants from Beneath?)
Planet of the Apes movies also tend to have a sense of humor - but other than the absurdity of chimps wearing skull facepaint to hunt deer, or a gas station in the jungle that still has working electricity connections and plays The Band, this is all pretty serious stuff, more so than you may be anticipating. I can't say I didn't enjoy the ambition and the seriousness with which director Matt Reeves takes the potentially absurd material, but I will forewarn that "entertaining" may not be the word you're looking for here.
Asked after the screening if I liked it, I had to admit I didn't know. I respect it for being as challenging and conflicted as it is , but it's not here to make you happy.