Complete and utter crap, based on a decent Michael Crichton novel. Amy's a girl in a gorilla suit...no, Amy's a gorilla, played by a girl in a gorilla suit. That's it. She has this thing on her arm that when she waves it, it speaks. Wave the arm up and down? Probably a dozen words and phrases. It's like having a Teddy Ruxpin doll on your forearm. Doesn't matter that the arm's moving in the same direction. Arm bands are much smarter than us silly humans.
Amy wants to go back to the jungle. Amy's keeper, Peter (played by Dylan Walsh, sporting a bit of an afro) gets the money to take her back from Dr. Frankenfurter (actually, it's Herkermer Hermolka, but since it's Tim Curry, it's always gonna be Frank), who wants to hunt for the lost city of Zinj. Laura Linney tags along because Ash from the Evil Dead movies found a really big diamond (from the lost city) and then disappeared. Winston from Ghostbusters leads 'em all through the jungle to certain death.
They find the city and get mauled by a bunch of mutant gorillas, grey ones that look like they have the teeth from the Bigfoot suit in Harry and The Hendersons. People die, gorillas get sliced in half by diamond-powered lasers, and the survivors (minus Amy) escape in a balloon.
Don't worry. You're not missing anything. The acting is way out there (much like Tim Curry's accent) and the effects suck.(Imagine me waving my arm up and down): Congo stupid movie. Ryan no like.