Cillian Murphy is one of the best actors working today, and his work has consistently been underrated by movie fans that aren’t familiar with his extensive track record. While many viewers have seen him thanks to his collaborations with Christopher Nolan on Batman Begins, Inception, Dunkirk, and now Oppenheimer, there’s also a large segment of fans who love him as Thomas Shelby on Peaky Blinders; the British crime series that is essentially a period version of The Sopranos gained even more popularity when it debuted on BBC and then went international on Netflix.

Murphy has been in many underrated gems, including his Golden Globe nominated performance in the coming-of-age LGBTQ+ dramedy Breakfast on Pluto, the Cannes Film Festival Palme d’Or winner The Wind That Shakes The Barley, and the delightful film geek romantic comedy Watching the Detectives. The buzz surrounding his performance in Oppenheimer suggests that perhaps Murphy could gain his first nomination at the Academy Awards; he shockingly has never received an Oscar nomination. However, Murphy certainly deserved one for his role in 28 Days Later, Danny Boyle’s zombie movie masterpiece that effectively changed the genre forever. Here’s why 28 Days Later is Cillian Murphy’s best performance.

Emotional Authenticity

George Romero had effectively created the zombie movie with his masterpiece Night of the Living Dead, and had updated the genre with the 1978 satire Dawn of the Dead and the 1985 military drama Day of the Dead. However, zombie movies released by filmmakers other than Romero in the years that followed simply tried to emulate his formula that had been so successful. It wasn’t until Boyle took a new spin on the undead in 28 Days Later that the zombie movie felt fresh again; Boyle used digital filmmaking techniques to make the film feel grounded in reality with a real sense of time and space. The realism made the film more authentic, and Murphy reflected that in his performance.

Murphy’s character, Jim, wakes up to a version of London that he no longer recognizes. The familiarity of the streets that he grew up on is gone, and he’s shocked to see that the cities are completely empty, and he cannot see any other living being in sight. Murphy’s reaction is one of confusion and fear that is rarely seen in zombie films, or horror films in general. It’s always obnoxious when the audience feels like they are smarter than the characters, but Murphy appears to be just as perplexed as to what’s going on as the viewer would be if they didn’t know that 28 Days Later was a zombie movie going in. The decisions that Jim makes from then on all seem logical, and Murphy’s inherent intelligence makes him perfect at capturing that side of the character.

Related: Cillian Murphy Wants to Return for 28 Days Later Sequel

A Father-Like Figure

Jim ultimately meets the woman Selena (Naomi Harris), the father Frank (Brendan Gleeson), and Frank’s daughter Hannah (Megan Burns). While Jim’s initial interactions with Selena are based on their mutual desire to survive, they slowly begin to trust each other as they both reach the realization that they must let each other know if they are infected so that the threat can be properly dealt with. Murphy and Harris do a great job at showing that Jim and Selena are becoming close because they need each other, not because they are falling in love. While it’s suggested that they may be forming a more romantic relationship than had previously been seen, the film is subtle in showing their platonic attachment.

What is quite powerful is seeing Jim become a paternal figure for Megan after Frank is infected, and the ground is forced to kill him. Murphy shows tenderness as Megan mourns, and helps guide her to make safe decisions once the group starts trekking into more dangerous territory where they could be exposed to a potential infection.

Related: Christopher Nolan Revealed Why He Wrote the Oppenheimer Script in First Person: "It's the Only Time I’ve Done That"

It’s nice to see Murphy in a softer role, as he is often typecast as villains in films like In Time and Batman Begins. Even his more heroic characters like Tommy on Peaky Blinders tend to be very cold and reserved, so 28 Days Later stands or even in comparison to those. Even though the Academy Awards rarely nominate horror films, and a zombie film has never received any major nominations, Murphy truly deserved to be placed in consideration for a Best Actor trophy.

A Complete Character Arc

Jim’s character arc concludes beautifully, and there’s a real sense of closure to seeing him escape with Megan and Selena after they ward off the threats of a ruthless military group that wants to sexually take advantage of the women in order to celebrate in a vile ceremony. The 2007 sequel 28 Weeks Later did not have Murphy, and though it was a solid follow up, the lack of a character like Jim made it clear that Murphy had added something special.

Murphy has hinted that it’s a role he might be open to returning to. He referred to Boyle’s script for 28 Months Later as “very appealing,” and recent reports indicate that a version of the final draft is now complete. It would be great to see Murphy return to his best role.