Plot, sci-fi elements and drama all are kind of mediocre, but the film has a handful of truly outstanding action scenes that make it very watchable indeed. The CG to create Smith's younger self isn't flawless, but isn't really distracting either. A pretty decent blockbuster, especially with Lee directing, but nothing truly great.
Early Marvel film, directed by Ang Lee. It's an impossible match of course, as a result the film is terrible. Lee lacks the skills to make a fun and frivolous superhero flick, Marvel lacked the budget to make it at least some kind of technical feat. It's long, badly acted, boring and way too serious.