I liked the movie even though it got really silly at parts. I thought the sidekick was borderline annoying. I really dislike people who go "duuuuh, I didn't understand one word you just said!" when they could just ask more questions and try to understand. I know having a lengthy discussion and explanation of some historical event wouldn't fit in the movie, but that fact doesn't get the sidekick off the hook. I guess I'm different than most people, because the part where he hugs the statue made most people in the theater laugh and made me wince. :) A lot of plot points made little sense and some were awful coincidental:
Click to see Spoiler:It's interesting that it took Cage so long to find Charlotte but yet found the rest of the clues in so short a time (days). What a coincidence that Cage hit metal 2 inches away from the word "Charlotte" when digging for the ship! The interior of the ship should have been filled with water/ice after all this time "drifting", no matter what the sidekick says about semisolid masses. The treasure room would have been found long ago by engineers, especially considering a subway track was built close enough for them to feel the shaking of the passing trains. There were more but I've forgotten them. I realize this is a "sit back and enjoy" kind of movie, but I couldn't help but wince at some of the flagrant problems in the plot.
Considering all that I still think it was a fun movie, with interesting good plot points (the trick that Cage's father pulls on the baddies at the end had me fooled, too) and I would recommend it to anyone that likes adventure flics!