That's not really a better alternative.
Although honestly, I don't think I care. If this is actually happening, it will suck. End of. It. Will. Suck. Alien is the best you can do with a monster on a space-ship. It took us 28 f**king years to test run the concept, and then wham, Alien did it. Alien nailed it. You cannot do better than Alien, because it is the best of what it is. It's the same reason shark movies never work; Jaws is just too good.