"Caved In" features several 'name' actors who are unfortunately reduced to acting in such a by-the-books film. Christopher Atkins and Angela Featherstone play husband and wife John and Samantha Palmer who, along with their 2 children work as guides of some sort (I don't recall is being specifically stated what they do other than take people around strange places).
Instead of going on a family vacation, John Palmer accepts on offer of a lot of money to take some less-than-respectable people into some ancient caverns to hunt for a tomb full of emeralds. So he does, while his family are left to explore above-ground. Naturally, things get out of hand in the old tunnels when giant (CGI) beetles begin attacking, and one-by-one the bad guys all begin to get killed off, or double crossed. The bugs begin making their way to the surface, putting Palmer's family in even more danger.
The acting is not too bad, well, it shouldn't be considering who some of the cast are. Christopher Atkins and Angela Featherstone both give decent performances, but poor Colm Meany, formerly of "Star Trek" fame is reduced to little in his role here. Monica Dean and David Palffy are fairly good in their roles as criminals, though one of them has a heart. Chelan Simmons spends the entire movie being unlivable annoying and / or running around screaming. It's a good thing her acting ability also improves for her next film "Final Destination 3".
Sci-Fi and Horror are combined often for films ("Event Horizon", "Alien") but do not always work well together. This is one of those cases where it's really personal preference, as the film lacks a lot of things, but it is not without trying.