The plotting was very different than it was for the first one. The first one had a fairly linear plot, while the sequel had several elements going at once. It's harder to pull off, but in my opinion they definitely did it. I loved the cast, including Scarlett. That scene with her in the car...

A random thought: I like that they kept the "new element" deal a bit vague, because a stable superheavy element beyond what we can currently produce artificially is hypothetically possible, though estimations of its lifetime vary wildly. Leaving the actual nature of the element open doesn't outright date the movie. (If you want to read more about this, search for the "island of stability."