Transformers 2 sucks as a movie and as a sequel, though as CG action robot porn, it's awesome. To wit:
Jetfire is an ancient British old-man Transformer with a robo-beard and giant walking stick. When he dies, Prime absorbs his jet pieces onto his body to fight whoever the final bad guy was, and then casually shrugs off Jetfire's weaponry and lets it crumple on the ground.
Roughly 70% of all the robots in the movie are unnamed throwaway characters. Most of these are never seen to transform.
The majority of jokes involve dogs humping each other, robots humping Megan Fox's leg, Shia LeBeof getting humped by a mega hot girl and being all awkward about it, and Shia LeBeof's parents humping each other.
I have no clue who the actual big bad guy was supposed to be. I don't think the writers did, either.
Skids and Mudflap act like racist blackface minstrel-show caricatures. They are also the most interesting characters in the entire film.
The logistics of a Decipticon perfectly imitating a human are never elaborated on. In fact, that plot point gets pretty much abandonded after Michael Bay realizes he can't milk any more sexiness out of an emotionless ladybot.
At one point the protagonists appear in Egypt with about half a line of dialogue explaining how and why they appeared there.
Transformers Egypt is functionally identical to the Middle Eastern country in the first film.
Grimlock wasn't anywhere in the entire film.