On the plus side, SUPERMAN RETURNS seems to have its heart in the right place. The humor and romance work really well. Clark/Superman/Kal-El (thanks largely to Routh) is still a character to rally behind. The cast, in general, all does a great job. And there are fun, crowd-pleasing moments: the shuttle/777 rescue, Clark's dog chasing his baseball, Luthor's thug playing piano with Lois' kid, Clark enjoying a mouthful of burrito seconds after Lois' night flight with Supes, Lois running into Lex coming out of the bathroom...all fun stuff.
On the downside, the film is missing its brain. Luthor's big plan is so incredibly ill-conceived and bizarre, it derails most of the movie. I mean, after the not-nearly-as-cool-as-they-should-have-been opening credits, the film actually starts with Luthor. So right off the bat, his plot is set in motion and dominates much of the film. Luthor's plot to split-off half of California in the first film might have been comically over-the-top but it made sense. Luthor's plot this time, to create a blackened, muddied, Kryptonite-laced supercontinent grown (nonsensically) from one of the Kryptonian data crystals he stole from the Fortress of Solitude in the hopes of selling beachfront condos, is absolutely absurd. Who would want to live there? Newly-formed California beachfront as the result of an earthquake following a botched government missle test? Yes. Cold, lifeless, dirty crystaline mass that destroyed most of the U.S. that supposedly killed "billions"? No. Say what you will about Hackman's "goofy" Lex in the first film...at least he had a brain. Spacey's Lex is meaner, more violent (a couple of moments made me cringe, actually) and occasionally, just as funny. But with the big picture, he's also fairly clueless.
And yes, as Devin said, the film ends and then goes on and on and on, including a situation I never needed to see Superman in, but that might be too much of a spoiler at this point, so I'll save it.
I hope Singer's next SUPERMAN film improves upon his first the same way X2 improved upon X-MEN. He's got a very good cast in place. He just needs a better story and more focus on what's he doing. Whereas BATMAN BEGINS felt in-the-zone (for the most part), RETURNS feels scattered-brained, trying so desperately to recapture the magic of the first film but forgetting what made the first film magical.
My two cents, anyway.
