(at around 25 mins) When Ada explains how she killed the operatives in the central command station, a security-tape replay shows Ada standing in the center of the room shooting outwards. But when Alice first enters the room, there are glass walls in front of each workstation, with blood splatters on the inside. This would imply that the workers were shot from behind. If Ada had shot from the center of the room, the glass walls would have been shattered.
(at around 23 mins) During the fight between Alice and the Tokyo zombies in the well lit, white hallway, Alice shoots and smashes the zombies, with blood shown coming from the impacts. However no blood ever appears on the white walls until the end, when only pools can be seen on the floor.
When the system has to reboot, a drawer opens revealing Alice's clothing for the rest of the film. When Alice walks into the hallway her shoes are a high wedge heel, while later in the film during combat scenes, Alice's heels change from high wedges to low wedged heels.
(at around 1h 12 mins) We see blood and bullets coming out of Rain's fingertips, but there is no blood in the snow.
(at around 1h 18 mins) At the end of the movie Alice lays flat on her stomach and rubs some snow off the ice to see an infected underneath it. In the next scene no disruptions to the snow are visible.
The Umbrella facility is located in northern Russia where the climate is shown to be arctic with snow, ice and heavy wind. However the characters have no problem with low temperature since they only wear evening dresses, no hats etc. Funnily the strike team wears bare t-shirts right after entering the elevator.
Even if coins could be fired from a 12 gauge shotgun, their ranges and ballistic impacts would be a mere fraction of traditional shotgun ammunition. If anything, they would be wildly inaccurate farther than a few feet, they would likely impact targets along their faces rather their penetrative edges and they would likely shatter from force of the initial shot.
(at around 7 mins) During the attack on the Arcadia, Alice is seen shooting quarters from her 12 gauge shotgun through the windshield of one of the tilt-rotor aircraft, killing the pilot. However, the diameter of a quarter is 0.955 inches; therefore, it would not fit in a 12 gauge shotgun, as the diameter of the shotgun barrel is only 0.729 inches. In addition, not only would a projectile such as this never penetrate an armored windshield as is found on tilt-rotor aircraft, the glass "spider-webs" with high energy impacts due to layered plastic laminates, and doesn't shatter, like plate glass would.
At around 12m, the car Alice and her daughter are in gets hit by a truck and flips over. That kind of an impact should have cause the car spin instead of flipping up.
(at around 52 mins) In the Moscow car chase a Las Plagas zombie is shooting at the heroes car with a DShK 12.7mm heavy machine gun. The bullets bounce off the car's trunk, while in reality they would go through killing the passengers.
The number of bullets vs their effectiveness seems to vary from scene to scene. Some protagonists can be stopped by a relatively low number of rounds; others require dozens or hundreds of impacts, including those from high caliber rounds which should create extensive tissue trauma. However it is commonly known that zombies don't die from gunshot wounds. They die by wrecking the brain. And then earlier in the series it became clear already even that doesn't always work.
The leader of Umbrella is shown to be able to move at superhuman levels of speed. Yet he is also able to avoid the problems with momentum and inertia that come with such abilities. Instead sliding past where he intends to stop, he able to precisely stop on a dime, regardless of the surface and the speeds required to perform his stunts (for example dodging bullets.) However it wouldn't be that hard to presume he learned how to use his superabillities.
(at around 34 mins) One of the dead Umbrella soldiers is breathing (his machine gun rises and falls on his chest as he breathes).
Despite the fact that areas just outside of buildings should be as cold as the open areas, character's breath is not shown. If the temperatures were truly below freezing , the condensation from their breath should be visible.
(at around 24 mins) After fighting the initial Tokyo dead in the Umbrella hallway, bodies are everywhere. When she finished off the J-Pop Girl, she see the horde coming for her. When the door opens & she runs for it, looking backwards from the door perspective, there are no bodies to slow down the undead.
Part of Ada Wong's outfit includes a Rosendahl Watch II digital watch, which seems to be acting as a more advanced smart watch.
When Ada says all of Alice's feelings toward Becky are "imprinted" the actress clearly originally said "implanted" but the line was changed in ADR.
@ around the 50 minute mark when the guy with the chainsaw starts attacking the guy in front of him the extra on the receiving end of this punishment can be verbally heard riling in pain, but in the close up you can see that his lips aren't moving.
When Alice opens the attic door a crewmember's head appears at the lower left of the screen.
During the opening sequence, as Raccoon City is shown on a 3d map, the view pans out to show the globe as the virus spreads, also showing earth as a mirror image, panning west from North America to Europe.
In Resident Evil: Afterlife (2010) J-Pop Girl is shown wearing high heels and has a purse around her body. In Retribution she can be seen wearing the purse again when in the Tokyo sequence, and footage is used from Afterlife implying she most likely has the heels on as well. However, when she is fighting Alice, her purse disappears, and she has no high heels or shoes on at all. However, it is nowhere implied that the recreation had to be an exact copy.
The scar on Alice's shoulder is on the wrong side. It should be the left shoulder, but this film has it on the right.
Milla Jovovich as Alice flubs her line in the opening narration when she pronounces Umbrella as "Umbreller" instead.