A spaceship crashes on a planet inhabited by dinosaurs and the (young, attractive, and scantily-dressed) crew struggles to stay alive. The special effects (the stop-motion dinosaurs) surprisingly good, for a low budget film. One by one members of the crew get eaten by carnivores, and you never know which one will be next. The debates amongst the crew members about various survival strategies are actually fairly reasonable, if you can get past the bad acting.
If you want to hear it with comedy riffs, get the "Rifftrax" version.
If you want to hear it with comedy riffs, get the "Rifftrax" version.