Oh, wow. Where to begin with Michael Bay's fourth installment of the Transformers franchise. I think he should have passed on it and let someone fresh take over. Jon Favreau maybe?
The good points: Autobots still fight the good fight, and giant robots fighting. Throw in some more "organic" aliens, and that's all cool.
And below be spoilers!
So years after T:DofM, the Battle of Chicago is still fresh, and plenty of political "See Something - Say Something" efforts are in action. Rewards, para-military hunting parties, etc. to round up the Transformers.
Basically, the CIA is using a inter-galactic bounty hunter, Lockdown, to hunt Autobots and Decepticons. Lockdown wants Optimus for he own reasons- something to do with "the Creators."
Meanwhile, back at the uber-techy KSI (headed up by Stanley Tucci- brill!), we find out that KSI has been able to create new Transformers from metal found on Earth and by melting destroyed Transformers. They call this metal "transformium" or something else worthy of groans. I guarantee Jim Jannard is laughing at that one.
Lockdown just muddies the story. He sole purpose is to introduce a bigger, badder "villain" in the Creators and bring about the Dinobots. Which could have been done in any number of ways.
I think the better story would have been to have the CIA/KSI develop the new Transformers from captured Decepticons. Then, under testing, Galvatron escapes with his new minions, and the Autobots need to find and fight them. To save Earth, or something.
During (or after, depending upon time) the fight, it is revealed that Optimus is being hunted by the Creators, and Lockdown appears, captures Optimus and takes him away. Roll credits. End credits scene is Lockdown flying in space, with Optimus hanging upside down behind him. Lockdown communicates with his employer about the success.
Things that really broke the escapism:
First fight with Lockdown and Optimus. You never saw it begin. Optimus driving off, cut to the "rally" car driving through old industrial site, then you see Optimus and Lockdown climbing a building. Uh, what?!
Michael Bay's fascination with females in white, that stay white no matter if they're in the desert, Cybertronian ship, or wherever.
Working on prototypes, but then finding in the Arctic the "transformium"-encased T-Rex. You would think they'd lead off with the discovery, then create the prototypes from that material. It just doesn't help with the story flow.
Overall, giant robots that fight is awesome. Seeing childhood toys on the big screen is awesome. Trying to create deep, intricate stories from a cartoon and toyline? Meh. Might as well try to make the Teenage Mutant Ninja Turtles aliens instead of mutants. Oh, wait...