That 2nd set of twins was actually Arcee and her two sidekicks in tow. I forget what their names are, but they're part of G1 to an extent. That I liked.
The twins... yeah. Why they talked, I have no idea. I can understand wanting to put crude or "stupid silly" humor in for the kids, and I understand that it's almost a given for something like that to be put in, but that was almost too much.
Soundwave had such potential. Serious, serious potential. He had the look of guy who'd kick ass and take names, but..... limited to monitoring communications? Friggin' weak. He did deploy Ravage, though. Serious nod to the oldskool with that one. :-D
Jetfire.... well, at least he had a contributing factor with Optimus. Slight nod back to the Armada cartoon is all I have to say.
That robot heaven.... best sense of it that I can make is that it was actually the matrix. All the knowledge of the Transformers is stored in it, right? There were several times in the old cartoon where Optimus interfaced with it and talked to some old guy (robot) in some virtual space and got advice from him. My thinking is that the knowledge contained therein (robot personalities and such) decided to interface with the human somehow. How is beyond me, but it's M.Bay. Don't question the man or your life will explode because he'll want another summer blockbuster.
The fight scene(s) with Optimus were... I leave it at outstanding. I loved them, simply put. The first one was so much more than I expected them to put in the movie.
Oh... and the Devastator transformation scene? Dude, I actually felt TINY with the way they shot him coming together.
SPOILERS BELOW!!!!!11
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This is twice now in our lifetimes that Optimus Prime has died. I actually felt a twinge in my chest when I saw the killing blow and realized what happened.
Plus, the twins holding their own against Devastator? WTF?!?!?

Oh, and last thing before I go. The Fallen has a direct link to Primus and Unicron. Notice how there was no mention of either in the movie. The best we got was the human guy saying, "Gotta make you wonder.... if God made us, who made them?" I hope I wasn't the only one who caught that little tidbit.