Much like in 'Gravity' everything is moving around as if it had little or no mass. Navigating a human body in micro gravity is a difficult task and must be done with great care. In this movie (as in others) these guys a flitting around like squirrels stopping their motion and changing direction effortlessly. In real life moving at those speeds would cause serious injury. A few times they even stop without grabbing anything. A related annoyance is the way the doors manually open and close effortlessly in no time at all as if they are made from nothing. Still, they manage to keep the creature out.
In the opening scene, the view of outer space from the International Space Station shows twinkling stars. Stars do not actually twinkle in the way we see them, but the twinkling is an optical illusion of the light from stars being refracted by the earth's atmosphere.
Some of the labels in Russian are incorrect. Miranda North's shield is literally translated into Russian as "Miranda Sever" (of course, in Cyrillic variant of this spelling). However surnames are not translated, and the shield in Russian should be either "Miranda Nors" or "Miranda Nort" (depending on the tradition of spelling English "th").
Also "Celsius" on temperature detectors was translated as "Celsiyu" (in Cyrillic; that means "by Celcius"); the real detector would be labeled as just "ºC".
At one point the space stations orbit is degrading and the thrusters are fired to put it back into a stable orbit. To accomplish this the thrusters seem to fire down or towards the earth, this is incorrect, to gain altitude they would need to orbit faster so the thrust would be from the back accelerating them into a higher more stable orbit.
When they are attempting to revive the man, they get a pulse back and someone says, "we have a pulse. Sinus brady, 98bpm." Brady is short for bradycardia which always indicates a heart rate of <60bpm (beats per minute). So if their bpm is 98, it would not be sinus brady, it would be Normal sinus rythm.
The astronaut "North" has her name in Russian below her English name. It is shown translated as the Russian word "Sever" which means the direction North. A name would surely be translated phonetically into Cyrillic, not fully translated into its Russian equivalent. This would look more like "HOPO" (with a vertical line through the last "O" to give the character for "F" (closest to "th" in Cyrillic).
At the beginning of the film, Ryan Reynolds goes outside to manually capture the probe returning from Mars. Given the actual speed of the probe is greater than the speed of the Space station, it would have been impossible for him to see let alone capture the probe.
The movie shows "Calvin" being attracted to and consuming oxygen from the lures they used to get it to the lifeboat as well as stating many times that since it is carbon-based, it needs it the way humans do. "Calvin" is from Mars where the atmosphere is 98% carbon dioxide. While there wouldn't be enough oxygen on modern Mars for the survival of the creature, it's explained throughout the film that it had been hibernating for possibly millions of years, since a period in which Mars had higher oxygen levels.
The crew attempts to kill Calvin by venting all oxygen to space. While the creature does survive for a few minutes outside the ship, it's explained that it needs oxygen for longer periods and would have eventually died outside the station.
Given the concerns about isolating the lab from the main space station, it's probable that they would have protocols in place that specifically required them to leave injured or "contaminated" astronauts in the lab in case of containment breaches.
The pod in which the Calvin is entrapped has the oxygen vented from it so that it is a vacuum inside the module. Assuming Sho Murakami could even have opened the door, the explosive force of the oxygen entering the module should have blasted him across the room and either killed him or severely injured him when he struck the other end of the module.
The crew spend much of the second half of the film trying to trap the alien and vent the atmosphere from around it to kill it / suffocate it as the repeatedly state it is dependent on oxygen. This ignores the fact the alien spent much time outside of the space station earlier in the movie with no ill effects.
Kalvin feels so much cold at habitable for humans, cold environment (arround freezing point), that it sticks to the torches. However, in space the temperature is -270 °C (0 K or -450 °F) and it spent there quite a lot of time, while it was "running" outside the space ship. At that temperature nearly all molecular motion ceases.
Early in the film Dr. Jordan (Gyllenhaal) is depicted floating weightlessly through the space station carrying his electronic tablet/device in his hand. At one point, when he sets his tablet down on a nearby workstation, the way the corner of his tablet drops from his hand reveals that he is obviously in a gravity environment where the tablet actually has weight.
The goof items below may give away important plot points.
After Calvin crushes Dr. Derry's hand it just hangs limply to show that it has been severely broken. Since they are in a "zero G" environment his hand should actually float along like the rest of his body.
David's pod couldn't have survived re-entry on its own as earlier Miranda has disabled the David's pod automatic flight plan back to earth thus giving him manual control. Re-entry is a complex maneuver that requires computer assistance and control along with complex calculations and specific set of re-entry angle. Just using a joystick to control the pod wouldn't work on re-entry as slight deviations will cause the pod to breakup or simply bounce back up to space.