Okay, I know. I hear what you're saying: They're space zombies, so they can work any way they want. Before I saw The Last Days on Mars, I would have agreed with you. But now, I'm still pretty sure this movie managed to get them wrong.
The Last Days on Mars stars a group of eclectically unlikeable astronauts just hours away from retirement, er, getting picked up after a six-month mission. Live Shrieber plays Vince, who is certain they're all going to die on the flight back home; there's a coward named Irwin; a selfish, fame-hungry bastard named Marko; Olivia Williams' Kim is just horrible to everybody; and there are a few others who doesn't even have personalities enough to be grating.
Although it's a miracle these people didn't kill each other at some point during their first week, their real trouble begins when Marko discovers evidence of bacterial life on Mars and doesn't tell anybody (despite the fact that this was in fact their entire mission). Of course, the bacteria turns people into space zombies, and the infected astronauts slowly pick off the rest of the crew, one-by-one, like virtually any other scifi horror movie you've seen before.
About all that sets Last Days of Mars apart is how maddeningly inconsistent these space zombies are. The bacteria kills them… but they still know how to use power tools and explosives. The bacteria spreads when people are cut… but not just by the space zombies' hands and teeth, but somehow anything the zombies wield, too, like knives or drills, yet the bacteria is not airborne. The space zombies can walk around Mars without a helmet on, but sometimes mild head-butting takes them out. The space zombies don't seem to want anything but to kill everybody, although there is one lone space zombie who decides to try eating people, but maybe he was just feeling peckish.
The Last Days on Mars isn't scary enough to be a good horror movie, isn't smart enough to really work as science fiction, and nothing bout the movie is interesting or original enough to be entertaining. I'd say you're better off watching Alien, The Thing, Aliens, Event Horizon, Pitch Black, Lifeforce, Dark Star, It! The Terror from Beyond Space, Ghosts of Mars, Planet of the Vampires, Mutiny in Outer Space, The Green Slime, Inseminoid, Galaxy of Terror, Forbidden World, Star Crystal, Jason X, Dracula 3000, Leprechaun in Space, or the like. Even if many of these aren't better movies than The Last Days of Mars, they're still going to be way more interesting in their crappiness.