The episode follows two old friends, Danny Parker (Anthony Mackie) and Karl Houghton (Yahya Abdul-Mateen II), reconnecting over a virtual reality fighting game.

Reviewers were divided over whether it addressed these themes in an interesting way, and some found it inferior to series three's "San Junipero", which also shows a queer relationship in virtual reality.

After they return home and have sex, Danny loudly plays the fictional fighting game Striking Vipers with his friend Karl Houghton (Yahya Abdul-Mateen II) as their preferred characters Lance and Roxette, respectively.

At the party, Karl gives Danny a birthday present: Striking Vipers X, the series' newest installment, and the virtual reality kit needed to play it.

That night, the pair play the game in their respective homes, falling motionless in real life as they fully experience all sensations of Lance (Ludi Lin) and Roxette (Pom Klementieff).

On July 14, as the three have agreed on an annual tradition, Danny plays Striking Vipers X with Karl while Theo goes to the bar without her wedding ring to meet a stranger.

The initial concept was for an office cohort to spend time in a virtual reality simulation as part of a team-building exercise, where they would prepare to perform the musical Grease.

[6] This story changed over time, and was informed by another source of inspiration: Brooker was reflecting on his days of playing the fighting game Tekken with flatmates in the 1990s, and thought there was something interesting in the "homoerotic" and "weirdly primal" nature of the situation.

[6][7][8] During the writing of "Striking Vipers", a variety of fighting games were used for reference, including Dead or Alive, a series where the characters have sexually provocative appearances.

[8] Jones noted that Danny's character regains a younger physique by entering the game, saying that there was a broader theme about ageing and "finding your identity when you don't have those staples that you've grown up with".

[9] In regards to the real-life kiss Danny and Karl share, Brooker thought the characters were telling the truth about experiencing a lack of excitement, but that it was different within the virtual reality game.

Harris said that the episode had a dark humour, and one of the lines which helped him understand it was Karl's "I fucked a polar bear and I still couldn't get you out of my mind", which became oft-repeated by fans.

Commenting that masculinity in the black community was a contemporary discussion point, Mackie recalled that Harris talked with him very early on about the relevance of race to the characters.

[17] Jones said of Danny and Karl's real-life kiss that both actors aimed to be clear that the excitement from Striking Vipers X was "not being echoed in the real world", and that the characters were relieved by this.

[22] Writing for Vox, Alex Abad-Santos compared that in "San Junipero", Kelly and Yorkie "play semi-artificial, digital-only versions of themselves", like Danny and Karl.

[26] Sexual and gender fluidity, infidelity and love and friendship are major themes, with The Guardian's Lucy Mangan writing that "every boundary is porous".

[28] Den of Geek's Alec Bojalad gave a partial answer that "there is at least some homosexual energy" but "Roxette and Lance's bodies are an essential part of the equation".

[24] Handlen said that Karl could be interpreted as a "potentially closeted trans woman ... but the text stops short of suggesting he's going to make any steps towards transitioning or understanding himself better".

[24][32] Another perspective came from Bojalad, who wrote that the episode sees video games as "a safe, consequence-free simulation space for little boys and eventually little men to work though the complex feelings they've so often ignored".

[31] Ahr similarly described that Striking Vipers X lets the characters "shed their culturally ingrained male inhibitions and admit their devotion to each other in a way that society discourages in real life".

[29] In contrast, Stubbs called Karl a "rich executive living the bachelor dream"; he fits the trope of a "ladies' man" and dates younger women.

The website summarises that critics found it "well-produced and thought-provoking", but that "holding back its emotional punch" makes it less powerful than similar episodes.

[26] In positive criticism, Stubbs said it was "one of the most sensitive, emotionally affecting" instalments, with Mangan concurring that it was "one of the most tender", and Vorel opined it to be "among the series' most pitch-perfect achievements".

[37] While Vorel saw Danny and Karl's reactions to be "profoundly well-earned", and Bojalad saw their sex scenes as "surprisingly raw and powerful", Bramesco did not see a "foundation of desire" leading to the first kiss.

[22] Turk criticised Roxette's description of sex as "the full orchestra" for women to be "awful" and "corny", and Bramesco and the Digital Spy critics Ali Griffiths and Morgan Jeffery disliked Lance's "don't feel like a gay thing" line.

[34] Sims found it "nervier" and "less swooning" than the other romance episodes, lacking the "rebellious fun" of "San Junipero" but also the "tragic tinge" of "Be Right Back" and "Hang the DJ".

[37] Griffiths and Jeffery criticised that "queerness is always neatly hidden away in virtual worlds" in Black Mirror, both in "San Junipero" and "Striking Vipers".

[40] Lodge criticised that "queer desire is treated ... as a disorienting byproduct of alien technology rather than a matter of the heart" and that the implications of Karl enjoying sexual experiences in a woman's body are "glibly grazed over".

[34][37] In contrast, Fiona Sturges of The Independent praised the "nuanced depiction of marriage, parenthood" and their consequent "erosion of spontaneity", and Handlen saw Danny, Karl and Theo as being given "a measure of dignity and compassion they might not have found on other shows".

[26] Mellor and Sims praised the filming style and scenery of the in-game scenes, with the former commenting that Harris "successfully created two totally different textures for each world".