Character mistake: Brad Pitt has control jets on his space suit - he uses them to accelerate him back towards his ship at the end, but somehow doesn't think to turn himself around and use them to slow down, hence slamming into the ship at great speed. Given the skill he demonstrates every other time in the movie, this only seems to happen for the sake of a dramatic arrival.
Character mistake: When Cepheus stops accelerating (which it would not have done until it turned to decelerate) crew plays in zero G's like amateurs who had never been in space. They were described as professionals with a lot of experience. They would never have risked fluid in the electronics by doing what they did.