Despite making "old vs. new" a central premise of the movie, The Expendables 3: The Squeakquel doesn't try to break any new ground in the action genre. It's main differentiating feature is a casting director who can't say no. If you like explosions and playing the game, "Oh, he still does movies?" then you'll love The Expendables 3.
At some point, you'll also start to feel bad for anybody over 50 in Hollywood who didn't get a speaking role. Sylvester Stallone, Jason Statham, Antonio Banderas, Jet Li, Wesley Snipes, Dolph Lundgren (who looks like if Denis Leary got stung by an entire hive of bees), Mel Gibson, Harrison Ford, Arnold Schwarzenegger, and many more all show up; even the poster for the film seems like the it wants to just say "Etc." to save space.
In case you're not familiar with the series, the eponymous Expendables are a group of aging freelance special forces—kind of like the Champions Tour for killing Russians. Expendables 3 opts to be more of a comedy than previous installments, focusing on old dudes hanging out, talking shit, murdering people, telling stories, reminiscing about the good old days, murdering people, drinking cheap beer, and murdering people.
After a failed operation with his classic crew, team leader Barney Ross (Stallone) puts together a much younger team and switches from an old-school shoot-'em-up style action movie to a new-school hack-and-sneak style. Shockingly, the old and new teams don't get along at first—but later discover they have lots to learn from each other! Do they sing karaoke together afterwards? Indeed they do, indeed they do.
It's impossible not to think about The Expendables movies as a not-particularly subtle metaphor for the actors themselves. Do the old guys still have it? Some do. Mel Gibson is great (even though that hurts me to type those words), and Statham and Snipes both put in a fine day's work. And surprisingly, Antonio Banderas as pretty enjoyable as comic relief. Stallone, Ford, and Schwarzenegger don't have it anymore (if they ever did). Schwarzenegger feels especially sad, walking around with an awkward beard and saying his catchphrase "Get to the choppa!" directly to the camera like he's expecting his trainer to toss him a herring each time.
Expendables 3 isn't without merit: Gathering-up-a-team montages are always fun, and this one inexplicably features Kelsey Grammer. So there's that? There are also some fine bits of shooting (helicopter vs. train, motorcycle vs. tank, boat vs. shipping container). And while they seem like every generic hero team, the young actors seem ready to carry the torch with aplomb.
Mostly, Expendables 3 does exactly what it's trying to do: kill off thousands of generic Eastern European extras while highlighting as many actors as you can legally put in one movie.