The tune that Wesker plays on the piano is Moonlight Sonata. The same piece is played in the video game Resident Evil by either Jill Valentine or Rebecca Chambers and in Resident Evil 5's Lost In Nightmares mini game by Jill Valentine.

While in the diner towards the beginning of the movie, a classic typewriter can be seen in the background. Typewriters are often used to save your progress in the games.

The movie never explains why the entrance hall of the police station looks so elaborate with its architecture and its giant statue in the background. In the games it's explained that the police station was a former art museum.

An infected woman writes "itchy tasty" on a window with blood. This is a reference to a line in a file titled "Keeper's Diary", found in the original game where the author became infected and slowly lost his mind.

"Jill Sandwich" is a reference to a cut-scene in the original 1996 game. After Jill is nearly crushed in a room and saved by Barry Burton, he tells her she was "almost a Jill Sandwich." The quote became a popular meme due to its ridiculousness and although it was altered for the 2002 remake, it was mentioned again in Revelations 2 and now in this film.

Capcom gave the filmmakers their blueprints to recreate the main halls of the Spencer Mansion and the RPD.

A video in the lab's basement shows the Ashford twins torturing a dragonfly, ripping its wings away and then letting it being eaten alive by ants. The same footage is a cutscene from Resident Evil: CODE VERONICA.

In the beginning of the movie Jill asks her friends what would be a worse death, swallowed by a giant snake or eaten by a great white shark. In the first game there is a giant snake and a flooded lab with sharks, both of which can kill you.

The movie's title appears in red bold letters. Color and font are identical to how they title appears in the first game.

Lisa Trevor's puppet is the same as Sherry Birkin's in the Resident Evil 2 Remake.

While in the armory Claire picks up a pack of shotgun shells. They are identical to the ones in the Resident Evil 2 Remake.

The movie ends with a status report. The first game starts with a status report. Font and color are identical in both instances.

Greg Russo's unused story and script, which he was developing with James Wan was inspired by Resident Evil 7: Biohazard (2017). Russo wanted to go back to scarier tone of original games and focus more on horror, just like Resident Evil 7 did.

James Wan was set to produce this reboot and Greg Russo was hired as the writer but the two later left the project with Russo leaving in November 2018 and Wan in December 2018 to focus on their work on Mortal Kombat (2021). Johannes Roberts was later hired as both the writer and director.

the infamous scene from Resident Evil (1996), in which an Umbrella lab scientist is eating one of the Bravo Team members, is shown. However, the man killed by the zombie is Kenneth J. Sullivan in the game, but in this movie, the man's name is Enrico Marini (played by Sammy Azero). According to Shinji Mikami the zombie's name is "Turning around zombie".

The film's release both coincide with the 25th anniversary of the video game and the release of Resident Evil Village (2021).

Two S.T.A.R.S. members that were in the original game but didn't show up in the movie are Rebecca Chambers and Barry Burton, despite having major roles.

When young Claire walks towards the child fort where Lisa Trevor hides, the music playing is "Go Tell Aunt Rhody" playing from a music box. The song was used in the opening and closing credits for Resident Evil 7.

In the Spencer Mansion you can see a painting behind Chris Redfield. It's identical to a painting in the video game Resident Evil Remake.

Lily Gao , who portrayed Ada Wong in the film, would later voice the character in the video game Resident Evil 4 (2023).

Enrico Marini (the man getting eaten by the turn around zombie) is a character from Resident Evil 0. He is the mission leader for the Bravo team and is second in command under Wesker at S.T.A.R.S. In the video games, he is the one to inform Alpha team (either Chris or Jill) that there is a traitor amongst them.

With this film being a reboot that's more faithful to the games, it is the first live-action Resident Evil film not to feature Milla Jovovich.  It is however written and produced by Paul W.S. Anderson and Jeremy Bolt who did the Alice movies.

Johannes Roberts very badly wanted to include more tyrants and monsters, particularly Mr. X and Nemesis among others. However, Roberts found difficulty trying to write them into the film's plot in a believable way, and ultimately decided not to include them.

Though Johannes Roberts confessed to having actually enjoyed Paul W.S. Anderson's Resident Evil (2002) film, he was still highly critical about how the films deviated heavily from the games, something which he hoped to correct with this film.

The film is based on and inspired by several video games that chronologically originally took place at different times.

Claire's wearing a necklace. Its pendant is a dragonfly wing. In the video game Resident Evil: Code Veronica you have to collect multiple dragonfly wings to advance in the game.

Chris Redfield is shown to drive a generic Jeep-style vehicle. In the video game Resident Evil 2 (1998) Leon Kennedy is shown in the intro to drive a similarly generic vehicle.

At the beginning of the movie an older lady is watching TV at the orphanage. If you look behind her you can see a poster that has a picture of the spray can used in the game to heal.

Near the start of the film, the nurse at the Raccoon City Orphanage is watching the TV show The Golden Girls (1985); specifically Season 2 Episode 9 "Joust Between Friends", which first aired on December 6th, 1986.

Earlier reports about possible casting choices for the film included Alexandra Daddario as Jill Valentine, and India Eisley as Claire Redfield. This was from back when all the characters in the script were much more closer to their video game versions, both with their looks and behavior. But following Constantin Film's insistence on more diverse casting and rework of female characters, changes were made which is why in the film Jill and Leon are race swapped, and why Jill and Claire have different personalities, with Jill as an unpredictable gun nut and Claire as a bit of a hotheaded conspiracy theorist.

Brenton Thwaites and Harris Dickinson were being eyed for Chris Redfield and Leon S. Kennedy.

The pistol Wesker used was his signature Samurai Edge, which should have been a standard M9 Brigadier, however this is his Resident Evil 5 version which is a Beretta M9A1. This variant of the pistol wasn't released until 2006 as it was updated with an accessory rail which the original didn't have.

Chief Irons tells Wesker the secret of getting women in bed is by playing songs from Journey. Later in the movie, Irons is listening to Journey while driving in his car.

The timeline of the film is not representative of the timeline in the video games. The "mansion incident" took place in July of 1998 in the original game series. This movie is set in late September 1998, which is the date of the events in the 2nd game, but includes both events happening concurrently. The two games that would have made more sense to merge into a single film are the 2nd and 3rd games.

Hannah John-Kamen who's Norwegian and Nigerian descent plays Jill Valentine who's Japanese and French descent.

This is Neal McDonough's fifth movie based video game after Street Fighter: The Legend of Chun-Li (2009), Company of Heroes (2013), Batman: Assault on Arkham (2014) and Sonic the Hedgehog (2020).

Robbie Amell is a fan of the Resident Evil video games.  He plays Chris Redfield.

This is Hannah John-Kamen's second movie based video game after Tomb Raider (2018).

Hannah John-Kamen is the second English actress to play Jill Valentine after Sienna Guillory, who played Jill in Resident Evil: Apocalypse (2004), Resident Evil: Afterlife (2010) and Resident Evil: Retribution (2012).

Robbie Amell is the second "Arrowverse" actor to portrayed Chris Redfield after Wentworth Miller in Resident Evil: Afterlife (2010) and Neal McDonough also appeared in the "Arrowverse" as well.

Brandon Seth Chinault was at one point rumored for Chris Redfield.

Other monsters which were going to be in the film but were written out due to last minute budget cuts and script changes include; Hunters, Chimeras, Crimson Heads, Pale Heads, giant spiders, Neptune, Tyrant Mr. X, and others. Hunter was Johannes Roberts's "personal favorite" creature, and one which he really wanted to include, but ended up having to cut it out. Roberts said how he was also considering finding a way to include Nemesis, but he never did any drafts where it was also included.

One of the several ideas to have Hunter appear in the film was to have another short action sequence taking place between the scenes where everyone escapes R.P.D station, and when they get to the Raccoon City Orphanage. Before they get there, they would go to Gun Shop Kendo to get some more guns and ammo, only to find the mutilated bodies of Kendo and his wife and daughter. Hunter would then show up and attack them, only for Leon to kill it.

The song in the official trailer is "What's Up?", performed by the all-female band 4 Non Blondes from their 1992 album "Bigger, Better, Faster, More!"

Both Robbie Amell (Chris Redfield) and Avan Jogia (Leon S. Kennedy) co-starred in Nickelodeon TV shows with Amell played Jimmy Madigan in True Jackson, VP (2008) and Jogia played Beck Oliver in Victorious (2010).

Two weeks before being cast as Leon S. Kennedy, Avan Jogia posted a photo of Leon on his Instagram account September 20, 2020.

This is the second time that Neal McDonough has played a villain in a cinematic reboot of a Capcom video game franchise, after playing M. Bison in Street Fighter: The Legend of Chun-Li (2009).

In the scene at Chris's home when he and Claire are catching up, there was going to be a reference to Elza Walker, the character from unfinished early version of the second game, known amongst fans as Resident Evil 1.5. Claire was to tease Chris and tell him how "certain miss Walker" was asking about him the last time she saw her, to which Chris would reply and mention her name, Elza. It's possible that this was cut since their relationship was changed to be more tense, so the dialogue in the scene was probably rewritten to make it less friendly, once Claire was changed into conspiracy theorist focused simply on Umbrella.

The town of Gatlin is mentioned several times throughout the film. This could possibly be a reference to Children of the Corn as Gatlin, Nebraska is the fictional town in which the story takes place.

Trailers also include several cut lines by Claire; "Every story has a beginning. Discover the origin of evil", "We need to expose Umbrella", "We have to contain this", "If we don't contain this, it could threaten the whole world", "The Umbrella corporation has been experimenting on this town since we were kids. People are getting sick. We have to stop Umbrella", "The world needs to know what's really going on", "We're gonna take Umbrella down". It's possible some of these lines were from the original ending, which based on the script for the film, had Claire and others talking after they get out of the tunnel how they're gonna make Umbrella pay for what they did.

Leon kills mutated Birkin with a rocket launcher. It's tradition in most Resident Evil video games to kill the final boss with a rocket launcher.

After Lisa Trevor was changed during script rewrites from another vicious monster and into someone who helps Claire and others, a new ending was also written where she shows up again and helps them escape and fights with mutated Birkin when it attacks the train and causes it to stop. Birkin however manages to grab and tear her to pieces, before Leon blows it up with the rocket launcher. This ending stayed in the script all the way during filming, but then had to be dropped completely after everyone realized how they didn't have any more budget and time to film this whole sequence, which is also why Birkin-monster ended up being just another lackluster CGI creature.

Lisa Trevor is a character who only showed up in the Resident Evil GameCube remake and Umbrella Chronicles. In the game she is a neutral enemy who was experimented on in the mansion and will chase Chris or Jill. In the movie, she is hidden in the orphanage and helps Claire by taking out a Licker and giving her the keys to the underground lab. Both appearances have her being disfigured while wearing skin face masks and having her hands cuffed in a block of wood.

At one point Chris Redfield is only equipped with a lighter. This is a reference to Resident Evil Code: Veronica.

Towards the end Claire is given a set of keys that unlock a secret passage. There are four keys on the ring and they are modeled after the four keys required to access most of the locked doors in the police station in Resident Evil 2 game.

In the mid-credits sequence, Wesker comes to and sits up in a brown body bag. This is a reference to the original game's Remake loading screen.

The truck driver who grabs a burger and eats while driving is a tribute to the truck driver of the Resident Evil 2 remake.

Ben Bertolucci dies inside a prison cell. He suffers the same fate in the video games, albeit from a different cause of death.

Wesker plays the piano to open a secret passage way. A similar event occurs in the original video game from 1996 and Resident Evil 5 Lost In Nightmares.

In the scene where William Birkin is in the lab getting the G-Virus, he is wearing a t-shirt from "Tall Oaks". Tall Oaks is one of the settings in Resident Evil 6, specifically Leon's campaign.

Ada is using Wesker to obtain the G-Virus. In the games she is using Leon.

The movie takes elements from at least 4 different video games in the series: Resident Evil 1 (1996), Resident Evil 2 (1998), Resident Evil: Code Veronica (2000) and Chronicles. It mixes them all up and combines them together into a different story.

In the mid-credits scene, Wesker complains that he can't see. Ada explains to him that it's a side-effect of the injection they gave to him. To help Wesker see, Ada gives him a pair of sunglasses. This is a reference to Wesker's design in the original video game where he's depicted as always wearing sunglasses.

In this movie Claire is very skilled at cracking door locks. This is a reference to the video games where Jill Valentine is called the "master of unlocking".

Johannes Roberts is a huge fan of John Carpenter. He based Leon S. Kennedy on Jack Burton from John Carpenter's Big Trouble in Little China (1986). Both characters are likeable and sympathetic anti heroes, yet they are completely incompetent, don't know what the hell is going on, and their only heroic deed is killing the main villain at the very end. One could even argue they are the comedic relief.

A helicopter crashes into the Spencer Mansion. This is a reference to Resident Evil 2. Except there it crashes into the police station. Although, in the GameCube "exclusive" game Resident Evil Zero there is a helicopter crash which is even more similar.

The Tyrant from the first game is missing and only William Birkin from Resident Evil 2 (1998) is the acting final boss.

The footage of the Ashford twins that Claire watches, along with the mid-credits scene with Ada Wong, are all intentional setups for sequels to this film, mainly adaptations of Resident Evil: Code Veronica and Resident Evil 4.

During the orphanage scene, Claire finds a video of two little kids pulling the wings of a dragonfly one by one, and then feeding the wingless dragonfly to ants. This is a reference to Resident Evil CODE: Veronica, in which you collect dragon fly wings to activate the Antarctic Base self destruct. In the game, one of the wings is found in the anthill room.

Ada is wearing her trademark trenchcoat. Although never confirmed she is most likely wearing her red cocktail dress underneath.

As she only has a mid credits cameo, this marks one of the few pieces of Resident Evil media to feature both Leon and Ada where they do not cross paths or interact on screen.

Mistakes

At various times in the movie, the actor's breaths would condensate as if it's cold. The movie takes place in September in the Midwest, which would be too warm for breaths to condensate.

When the trucker is with his dog after Claire has left, the dog bites the truckers left hand but in the next cut he is holding his right hand in pain.

When Claire tries to enter Chris' house the front door is locked so she breaks into the back door, but later the child from the neighbors house enters the front door and hides under the table even though it's still locked.

When the Huey helicopter crashes into the house, the resulting explosion and fireball consumes the room. However, in the next scene, all of the wood and books surrounding the helicopter are untouched.

The motorcycle skid sounds like a car (multiple tires), but any skid sound on a wet road would make no sound.

Bravo team's police car, numbered 116, which is found upturned near the mansion, is also seen later in the police garage when the police chief is running from the dog.

Following the helicopter crash in the library, two of the characters not only survive the fireball, they stand and casually chat in a room full of flames and debris. The room is suppose to be full of heat and choking smoke, yet they act like it doesn't exist.

Claire doesn't actually pick her brother's front door lock. She puts a knife to the seam of the door and frame well above the actual lock.

When Claire turns on the movie projector in the basement, normally somebody would have to set it up first as the last person to watch it would not have. Also, while the bottom reel was running in the right direction, the top reel was running in the wrong direction for playback.

While the helicopter pilot is waiting for the rest of the team, he's playing the "Snake" game on a Nokia phone. However, the model being used (a Nokia 5125) wasn't released until December 1998, while the movie is set in September 1998.

A keyboard is seen with a key bearing the Microsoft Windows logo. Such a keyboard wasn't introduced after the time in which the movie is set.