Let's be clear, this is film is better than the "one star reviews" would have you believe. Does it have its problems? Sure. The "nine star reviews" are also over the top. There should have been more breathing room for the setup in the beginning of the film, so that we get to know the characters better and care more for them.
Having said that, they clearly made the most out of a very limited budget... and at times I was impressed with what they managed to pull off. The astronaut suits looked pretty neat, as did the ships and the combat scenes.
Part of the problem, is that most of the story (from the second act onwards), happens on a mostly deserted planet. It's why the plot had to be pretty basic and some reviewers complain about it being slow. However, that's mostly a factor of the limited budget they had to work with.
Could it have been better? Yes, but you shouldn't go into this expecting the same experience as you would with films that have ten (or one hundred) times the budget. If you have some sort of concept of how difficult it is to make something yourself, you can appreciate that these kids did a good job... and also that there's still room for improvement!