Atop the clock tower is one of the spots where Leon can use his binoculars to view specific spots and potentially trigger small cutscenes; in this case, Leon sees Ramon and his men taking a tranced Ashley away behind a big door; however, while in the binoculars, Leon can also see the small path with two crossbow enemies that leads to that door, even though, from that point, it should be impossible for him to see that, as part of the clock tower is in the way.

The Killer7 weapon is a reference to Killer 7, a Capcom game originally released for the GameCube and PS2.

Leon's Combat Knife is the same one Marvin gave to him in Resident Evil 2 Remake.

Leon's starting pistol has "Kendo" engraved on its side. This is a reference to Joseph and Robert Kendo, the gunsmith and gun salesman respectively in Resident Evil 2.

The Striker Charm gives you an 8% movement speed boost. This is a reference to the famous Ditman Glitch in the original Resident Evil 4.

The You're Small Time! trophy is a reference to Leon taunting Saddler in the original Resident Evil 4 game.

While wearing the pinstripe suit as Leon with the Handcannon equipped. If you have unlimited ammo for it unlocked, when you press reload Leon will do a stylish gun flip instead.

Ashley's pose when sitting on a barrel in the gun range is based on a piece of promotional art from the original Resident Evil 4.

During the game, Ashley makes a comment about being a 'master of unlocking.' This is the same title that Barry Burton gave to Jill Valentine in the original Resident Evil.

At one point while playing as Ashley, you'll come across a mounted elk's head that falls from a wall. This is a nod to a nearly identical scene in Resident Evil 3.5 which is one of the beta versions.

When you're in the shooting range, pay close attention to the music. It's the same song that played in the intro of the original Resident Evil 4.

The Attache Case Charms are all based on the character models from the original Resident Evil 4.

The Wave Goodbye, Right Hand trophy is a reference to a joke Leon makes about the Verdugo in the original game.

The Grilled Big Cheese trophy is a reference to Luis calling Mendez "The Big Cheese" in the original game.

The challenge for surviving the villa siege without using any wooden planks takes its name from a joke Luis makes during the same part of the original game: "Did you send out those invitations? I told you, no more than fifty people!

Like most of the boss-related trophies, "You Used to Be a Good Guy" is a reference to the original Resident Evil 4 game, where examining Krauser's mutated corpse would prompt Leon to lament his former comrade's fall from grace.

The No Thanks, Bro! trophy is a reference to a conversation Leon and Salazar have in the original game.

If the player interacts with Saddler's throne, Leon will sit down on it in a manner similar to how Count Dracula sits on his throne at the beginning of Castlevania: Symphony of the Night.

Development of this remake had already started in 2018. Capcom collaborated with studio M-Two, but they eventually cut ties following creative differences. M-Two wanted to stay very faithful to the original game, while Capcom wanted to take the remake into a different direction. In early 2021, Capcom moved the development in-house, and many team members that have already worked on Resident Evil 2 (2019) returned.

In the original game, completing the main story could unlock two game modes: "Assignment Ada" and "The Mercenaries." Additionally, "Separate Ways" was a new campaign included in the PS2 port. However, in the remake, they were released as DLCs. "The Mercenaries" was released as a free update in April 2023, and "Separate Ways" was released in September 2023.

In Chapter 1, after passing the farm and approaching the cabin you will defend later with Luis, there is a path on the left which shows a vista of the remnants of an old Gondola lift. This is the Gondola Leon rides in the original Resident Evil 4 game to fight Bitores Mendez. It is replaced in the remake with a chase sequence involving Mendez before you fight him.

Capcom confirmed that the game would be darker and scarier than the original game. It features more terrifying character designs, more realism, a tenser atmosphere, and enhanced environments. It also allows the player to walk while crouched and perform stealth kills, and use knives as defensive weapons when grabbed by enemies. The remake also minimizes the use of quick time events, and adds several mini quests for which the player can earn additional credits from the merchant, such as additional Blue Medallion quests beyond the village area.

Lily Gao reprised her role as Ada Wong from the live-action movie Resident Evil: Welcome to Raccoon City (2021).

The remake corrects several plot holes from the original game, the most prominent being when Leon is captured with Luis, and the game shows him having no items and needing to recover them. The original showed several scenes where Leon was captured or threw his knife at enemies, but miraculously recovered these items when game-play resumed.

Saddler is actually a believer of the Cult in this version and gives sermons all the time; appearing as visions to Leon due to his infection.

In the original game Saddler was just conning and taking advantages of the cult. He was much more lucid and aware he was the bad guy.

A new type of enemy not found in the original are called 'Brutes', which are large men wearing bull or pig masks, and often wielding large hammers. They may have been inspired by similar-looking Executioner Majinis from Resident Evil 5 (2009).

In the original Resident Evil 4 game, Leon meets Luis Sera and pronounces his name as "Louis". In the remake of Resident Evil 4 game, Leon meets Dr. Luis Serra Navarro which shortened is Luis Serra. Basically in the new remake they added an extra letter in what was his last name which now is like the first of 2 last names. Also Leon pronounces his name correctly in this game.

Some of the content in the "Separate Ways" DLC was originally intended for the main game, but was ultimately cut and incorporated into the game's expansion content.

Nick Apostolides does the voice of Leon Kennedy, reprising his role from Resident Evil 2 (2019).

Saddler is given a second stage boss fight, which gives him a new form that takes inspiration from the Ouroboros virus.

This is the third Resident Evil remake game to use red letters for the "R" and "E" and remaining letters in white for the game's title design.

In keeping with changing times and attitudes, Luis' "ballistics" joke about Ashley's breasts from the original game was removed; she now objects to him calling her a "missing señorita". Ashley is also more resourceful and can climb down ladders and some ledges herself, whereas in the original, she would almost always jump down and let Leon catch her.

Capcom rejected M-Two Studio's version of the Resident Evil 4 remaster while it was still in production and was developed enough that they had tested some playable versions. Similarly, Capcom rejected at least four different versions of the original Resident Evil 4 before finally settling on the released version, with the four versions known as "Fog," "Hook Man," "Hallucination," and "Zombie" having been completed enough for demos and trailers for each to be shown.

It's revealed Ada planned to help Leon escape via the jet ski. She was just teasing him with the offer to leave via helicopter.

Ada is revealed to have shot the church bell that saved Leon from the Ganado.

Whenever Leon is on a call, a vertical screen will pop up to show whomever is talking. This is purely aesthetic as Leon doesn't have any device to look at who's talking. Just like how the loading screen on the original showed Leon and his contacts talking.

It's shown being wounded by a Plaga monster is enough to spread the infection; showing that they can reproduce even from small genetic material.

Leon obviously knows Spanish. No one would write in English in Spain if it's not their native language.

Everything he's reading is translated in his head for the players to read.

Wesker getting directly involved was never in the original version.

Even in this remake, what Ada plans to do with the amber is never stated.

Unlike the original game, it is possible to avoid the first battle against the villagers entirely. When the player uses a sniper rifle in the New Game Plus, shooting the church bell will make it ring, which causes the villagers to go to the building earlier. However, just like in the original, the battle with Verdugo in Chapter 10 can be partially skipped; he needs to be fought off or avoided until the elevator arrives, after which the player can use it to escape the area and leave Verdugo behind.

Leon and Krauser talk about Operation Javier, a mission that took place two years before the events of this game. It was one of the main scenarios in the first-person shooter game Resident Evil: The Darkside Chronicles (2009), which was released four years after the original Resident Evil 4 (2005). The mentioning of the mission as well as as an in-game file thereby make that part of Darkside Chronicles canon.

In the original game, Leon has a boss battle with a U-3 creature. That boss battle was not adapted into the remake. Instead, it was moved to the 'Separate Ways' DLC in an altered form, where Ada has to fight the creature.

The game contains much more in-game files than the original, which provide additional backstory to the Plaga outbreak in the area. One revelation is that Ramón Salazar suffered from an unspecified illness, so his mother invited Lord Saddler, who is implied to have killed Ramón's father, into their castle in order to cure him, which is probably how they were able to convert Ramón. It is also suggested that normal Plagas cause brain damage that makes the host very cooperative, but also severely reduces their intelligence. Ramón and Ashley have been infected with specially developed Superior Plagas so that they retain their intelligence. Lastly, the identities of the two Verdugo creatures are revealed: they were Ramón's former housekeeper and personal servant.

In both the original game and this remake, Saddler is a manic cult-leader terrorist who has kidnapped Ashley as part of a plan to infect people close to the US president with the Plagas. In this remake, he makes a few appearances throughout the game, but doesn't properly meet with Leon until the final part. The remake also makes it much more explicit that Saddler intends to use the infected Ashley to get to the President directly, and from there, the world.

Mistakes

Knives do work better in close counters, but not when someone is pointing an automatic weapon to your back.

The flaming statue in the clock tower doesn't set the wooden structures on fire.

The messages that Leon receives show a video, yet he cannot possibly see a video since he only has earphones.

Spelling and punctuation errors in subtitles.

The crosshairs in the bio-sensor scope do not meet in the middle. Scopes always have crosshairs that meet in the middle for precision.

At the bottom of the dungeon there are torches lit even though no one could have lit them.

There are full pallets in the castle where no forklift could have reached.

A handgun is not capable of blowing limbs off.

Weapons and equipment are carried in a briefcase, but Mr. Kennedy isn't visibly carrying a briefcase.

Leon does not cock the assault rifle after loading it.

The computers in Luis' laboratory are on despite him not being there in a while. This is not a plot hole since it's not known how long ago Luis left his laboratory, or if someone else had access to it.

Luis Serra is a highly sophisticated individual, yet he told Leon his real name. In order to evade the US government from persecuting him, he should have used a fake name.

At the castle dock, Krause could have sabotaged the unused boat so that Mr. Kennedy couldn't follow him, but failed to do so.

Krauser made it very clear in a tape recording that he had an entire battlefield set up and that he wanted to challenge Leon based upon his skills. So it's obvious that he wanted Leon to follow him.