Corrected entry: There is one major mistake that seems to happen a lot in this movie. The vacuum of space. When the main character and the the other guy are in that ejection pod, the glass starts breaking. What ever should they do? The other guy says: "Quick, exhale!". That's right, their plan is to hold their breath in space. He breaks the glass, and instead of their blood boiling, they fly to their ship with the aid of fire extinguisher.
Corrected entry: In the scene where Cale wakes up from his nightmare and looks out to see the Drifter colony. When it shows the complete shot of the Drifter colony if you look in the bottom right corner you can see the Death Star from Star Wars.
Correction: This is definitely intentional. I guess it is a tribute to the Star Wars trilogy, so it is more like a trivia than a mistake.
Corrected entry: If you notice in the end, none of the DNA samples on the Titan were removed.
Correction: The Titan may only be able to replicate DNA into creatures if they are on-board when the process begins. Either that or no-one on-board at the time of activation knew whether they should take them off or not and were more concerned about using the Titan to absorb the energy about to be fired at them.
Corrected entry: When fleeing from Earth, the father takes a ring off his finger and put it in his 6 year old child's finger, and it fits perfectly.
Correction: If you look carefully, you can see the ring is quite bulky, and doesn't fit as well as it should.
Corrected entry: In another scene the other guy gets shot when he is in his space suit. You see a trickle of blood. That means there must be a hole in his suit. Once again, the vacuum of space doesn't kill him.
Correction: You can survive for several minutes in a vacuum. It's not pleasant, but survivable.
Correction: According to NASA, if you don't try to hold your breath (the movie character says it: "Exhale") you can live up to 30 seconds. If you inhale, you can't.