1. It's a cute concept
2. It promised interesting CGI stuff
3. What else is there to do on Sunday Night? My wife was deep into making a quilt.
My advice -- go to "Pirates of the Caribbean" twice. This one has it's moments, but about 2/3 the way through, it stop making sense, you stop caring about the characters, and the psychotic liberties taken with physics, geography, and common sense take their toll. It probably doesn't behoove one to try and make naturalistic sense out of a movie concerning a team of fictional characters, but this one definitively goes wrong.
ALMOST worth seeing though for the Mr. Hyde sequences. I don't know how much of it is rubber appliances and how much is CGI, but it's visually arresting. Plus, the Hyde bits aren't filmed the way most of the action is, so you feel like you're actually seeing what's going on. Nemo especially seems to just walk around with bad guys falling down around him; you can't even really see what he's using for a weapon, and a lot of the Quartermain action is so jerky and jump cut it makes you queasy.
Peta Wilson is pretty yummy though.
It does redeem itself by making Roger Ebert wax eloquent over it's faults:
'Now back to that speeding car. Its driver, Tom Sawyer, has been sent off on an urgent mission. When he finds something--an underwater bomb, I think, although that would be hard to spot from a speeding car--he's supposed to fire off a flare, after which I don't know what's supposed to happen. As the car hurtles down the non-existent streets of Venice, enemy operatives stand shoulder-to-shoulder on the rooftops and fire at it with machineguns, leading us to hypothesize an enemy meeting at which the leader says, "Just in case they should arrive by submarine with a fast car which hasn't been invented yet, I want thousands of men to line the rooftops and fire at it, without hitting anything, of course.'
I guess he had trouble suspending disbelief too!