If I have to speak of this movie, well, can't go turning back.
Okay, first off, the story. After the events of DotM, the United States government decides that the Autobots are hindering Earth after the explosive Battle of Chicago, and now, with humanity against them, robotics engineer Cade Yeager (Mark Wahlberg, Three Kings), his daughter (Nicola Peltz, The Last Airbender), and her secret above-age Irish boyfriend Shane (Jack Reynor, What Richard Did), must protect the Autobots, and Earth, from a "mysterious" new menace named Lockdown, a former-KSI-operated-that-now-acts-like-Megatron Transformer named Galvatron, and a corrupt Kelsey Grammer (Toy Story 2), while also trying to stop their efforts in detonating the MacGuffin called "The Seed", which annihilates anything in its path and turns them into metal.
And you thought the All-Spark, the Matrix of Leadership, and the Ark were enough plot devices in these movies...apparently not.
The first twenty minutes of the film are, and I'm not even kidding here, actually decent. Yeah, you have your traditional Michael Bay trash humor, but even that's toned down. Yeah, you have a daughter and a boyfriend who can't act worth crap (even though the boyfriend is, ironically, starring in better movies, like the upcoming Justin Kurzel-helmed Macbeth), but even then you can, at least, breathe a little easier knowing that the other cast is gone to different (and better for some of the actors) films.
The minute the entire Autobot cast is introduced, though, it all plummets into the same old Michael Bay shenanigans, which will really anger those who were wanting some actual change of pace for these movies, but, nope!
I'll give it this, though. The tone of this film is thankfully darker and less humorous when compared to Fallen and Moon, and this film is thankfully saved from being complete dog-crap by Wahlberg's charismatic effort at acting in this film, but, the film still doesn't know what to do with most of its actors.
As mentioned, Wahlberg is actually likable in this film, as in, he's more helpful when times are dire and actually contains some funny moments (mad props to his one scene after they escape from Lockdown's ship when he snaps at this one guy who threatened him that he had insurance to pay for his mutilated car.) Even Stanley Tucci's character gets some actual chuckles in the film, albeit few.
The film also contains an ACTUALLY FLESHED-OUT main villain in the form of Lockdown (Mark Ryan, Transformers (2007)). Unlike the other villains who were in it for world domination or destruction, he's just in it for adding Optimus Prime to his collection of trophies, which, for Michael Bay standards, is a plus.
Now with those few positives, we have a truck-load of negatives.
The film, from a narrative sense, is just a copycat of the films before it and other films, both recent and classic. To quote IGN's review, the plot to hunt down the Autobots is similar to X-Men: Days of Future Past, the plot to find the Seed is NOTE-FOR-NOTE to the other plot devices from the other three films, and I think you know where I'm going with this.
It also bites that for a film about robots beating the mechanized s**t out of each other, it is nearly three hours long. When compared to the other ones, the length is the equivalent of an endurance test and a blasting zone combined. Even the most die-hard "Bayformer" will find 165 minutes to wear them down eventually.
Michael Bay fans will definitely enjoy another round of explosions, but for the general movie-goer, you're not only watching the same overlong crap that we're now used to, you're watching the equivalent of Michael Bay giving a three-hour long description of his Transformers figurines and toys with pictures of the firecracker that exploded his toy train that he filmed when he was eight years old with an 8mm camera and got grounded for it.