The first thing you need to know about 'Shadowzone' is that it's a blatant rip-off of a dozen other films from the same sci-fi/horror genre. The first that comes to mind is 'Alien,' but there are elements of plenty others in there, too.
It doesn't have much of a budget, which is a shame because there is a decent idea buried somewhere in it. What lets it down is that there isn't enough invested in the characters. Every one is a total stereotype and you know who'll be monster-fodder and who's going to make it from the word go.
It's about an investigator who does to a top secret military base to investigate the death of a worker. Once there, he finds the scientists are dabbling in doorways to other dimensions (never a recipe for 'happily ever after'). Then, we have a monster who - remains relatively unseen - as it bumps them off, one by one.
The acting isn't great, the special effects are stretched and what tension is pretty much directly lifted from Alien (check out the 'motion tracker' type scene which is almost totally taken from the scene in Alien where Ripley observes Dallas while he treks through the vents, plus the music which sounds almost identical).
It's not the worst 'monster-munching' movie out there. There are some nice moments here and there, but the overall vibe of 'seen it all before' outweighs what little good is there.
