I’ve seen both the normal and Imax version, and enjoyed it a lot.  In fact, the two things that annoyed me first time around (the twins and the length) grated a lot less on a second viewing.  Aside from the fact that I found the twins annoying as the film went on (but very funny at the beginning), that’s all I’m saying about them.

All in all, I thought the film did exactly what a good sequel should, which was just taking what worked from the first film and do it twice as good.  The plot is pretty much identical to the first, but there’s some more focus on the actual Transformers this time.  There’s some nice scenes between Megatron and Starscream which flesh them out, and Optimus gets some great moments.  The forest fight stands out as a high point of the film, where Prime takes on most of the Decepticons single-handed.

The returning cast did a good job as well, but interestingly for me, this time the film was stolen by John Turturro’s Agent Simmons.  In the first film, I wasn’t really bothered about his character, but in this sequel I thought he was hysterical.  Shia LaBeouf turns in his usual great performance, again getting to show off his comic timing perfectly whenever Sam starts getting flustered, as in the first film

In terms of the Transformers themselves, Jetfire probably stole the film for me.  The idea of a cantankerous old Transformer was really well played out here, and very funny.

There’s not really a huge amount to say here.  If you enjoyed the first one, you’re on pretty safe ground with the sequel.   Its great fun.