Oh Dear! Another Multi-Million Dollar movie spoiled by the most trivial aspects which make the whole thing unbelievable. How many more of these Martian-based movies must we endure? I'm not going to bore you with technical details, but those of you with a Scientific background will be aware of how ludicrous many of this plots premises really are. (Minor example:- A Sugar-bomb to blow off a pressure door? Even If It WERE possible, would It really not damage the Spacecraft? Remember, It's an 'open' bomb, not an enclosed one, and so It would not contain and safely direct the blast.) I'd hoped for much more...Instead, we get more of the same. Suffice It to say that a man In the position In which our 'Martian' finds himself - struggling to survive In an every-second-counts matter of life and death and surrounded by multiple obstacles - does not have the time (never mind the Will) to keep himself totally clean shaven! Personal hygiene would be bottom of the list of priorities In such a drastic situation. All those Months and never so much as a tiny bit of bristle on his chin? Can something so obvious really be beyond the common sense of a Director with an enormous budget? A man under stress doesn't shave, period! Oh, but hang on a moment...after about 18 months, bang- a full beard, seemingly overnight! Likewise - and perhaps even more stupid - his hair remains exactly the same style and length. It doesn't even become dirty or disheveled! Some will think I'm being petty, but obvious errors like this utterly spoil the 'believability' of the whole plot and destroy the continuity despite how many 'Sols' have elapsed. I can live with the fact of this plant-studying astronaut managing to grasp the Engineering, Electrical and multitude of other skills required to survive (not to mention the Initial self-surgery...what a Guy!!) but some of the Science(i.e. Pseudo-Science)Is just plain silly. I'd hoped for so much more but sadly It's yet more American flag-waving twaddle of the first order.