After an hour or so of flying back and forth on the first level of the "Empire" section, I'm at a loss of how I'm supposed to get out. I used the Snowspeeder tow cable on the 10 AT-STs, and no matter where I go, they just keep on coming, with no apparent exit (for me, at least) and no decrease in amounts of Imperials.
So, I went ahead and started the ROTJ section, and had a lot of fun. The only thing I was kind of surprised at was Luke's relative ineffectual lightsaber use against the Gammorreans in Jabba's Palace (the Force choke works really well, though), and the seeming nigh-invincibility of the Rancor. I also found it kind of funny that you can use the Jedi Mind Trick on Lando when he's wearing the Skiff Guard disguise.
Overall, I have to say that I really love the first Lego SW game, and this one, like Matt says, seems to be just as good as the first one.