If you enjoyed Danny Boyle's '127 Hours,' you may also like the underrated 2004 movie 'Open Water.'

Both films are based upon true stories, in which people are caught in physical and psychological dilemmas that threaten to kill them (and, incidentally, take one of their limbs).

Viewers who have seen '127 Hours' know the story: mountain-climber Aron Ralston (Franco) slips and falls while hiking in Utah and gets his right arm trapped by a boulder. For the next 127 hours, Ralston fights to survive, and quickly realizes that the only way to get out alive is to amptuate his own arm.

In 'Open Water,' director Chris Kentis tells the real-life story of Tom and Eileen Lonergan, a couple who takes their rocky relationship on a scuba-diving vacation in the Great Barrier Reef. Things get scary when their hired drive boat accidentally abandons them in the waves, then even more scary when they realize they're surrounded by hungry sharks.

Related stories:
Oscars Made Easy: Why You Should See '127 Hours'


Though '127 Hours' and 'Open Water' share a similar plot, their style and execution couldn't be more different. Boyle's movie is filmed in the lush, color-rich, occasionally fantastical fashion of his previous movies like 'Slumdog Millionaire' and 'Trainspotting.' Working on a much-smaller budget (half a million, compared to Boyle's estimated $18 million), Kentis uses a raw, digital video aesthetic to capture the mood, and is every bit as effective as Boyle.

Another difference lies the acting. Boyle's film is stocked with big-budget names like James Franco, while 'Open Water' features skillful work by committed -- but lesser-known -- actors like Blanchard Ryan and Daniel Travis. Still, Franco, Ryan and Travis are equally good in their roles, as they perfectly capture the claustrophic fear of being trapped and fighting for your life within a confined space.

Watch the Trailer for 'Open Water'


Ultimately, no matter how difficult it may be to sit through these movies, or how different they are, the payoff is the same -- and more importantly worth it. Fans of '127 Hours' will leave the film inspired by Ralston's determination to survive. 'Open Water,' meanwhile, asks a very important question: What happens when the odds are insurmountable?

To find out, you gotta watch the movie.

Watch the Trailer for '127 Hours'