The problem with "Movie Critics" is that they watch movies as a profession and thus anything that doesn't leave them reeling with shock or buzzing with new ideas to justify their time sitting down and watching it is panned as unwatchable.
The truth is that most of us watch a lot of movies for pure escapism and enjoyment in preference to doing something rather dull in our normal lives. We watch the film to fill an evening or as a background to night in and it doesn't matter to us that its all claptrap, so long as its enjoyable.
Congo is not going to challenge anything in your head, but as a popcorn and soda type film, its hugely enjoyable. The pacing is good and feels epic without being slow. The story, as daft as it is, keeps the viewer on edge and the actors revel in their parts knowing that this is not the next Clockwork Orange.
Perhaps the real criticism is the fact that it is based on a novel that is scientific and thoughtful in its approach. I can imagine if you are a fan of the novel, the film will seem disappointing simply because of its different approach.
There are some terrible movies that seem to go on forever without getting close to being interesting, Congo is not one of them - Jerry Goldsmith's musical score sooths the action and terrible lines are delivered with a zest that suggest the actors know its looney, but aren't going to let that stop them (and us) getting on with having a good time.
A little scary in places and with great set pieces and characters getting what they deserve at the hand of rabid gorillas in a lost jungle temple, this film is under-rated. Great to have on as thin flick that isn't nearly as bad as critics will lead you to believe. Just Enjoy It!