Acceptable Targets: While the episode was pretty well-received, some fans and a few critics argued that it treated nerds (and more specifically, Trekkies) as Acceptable Targets. However, the majority opinion is that it attacked only one unfortunate kind of nerd: the entitled, rude sort that uses their online persona to bully others and compensate for real-life frustrations. Similar to how Misery didn't attack all enthusiastic media fans, just the aggressive and entitled ones.
Alternative Character Interpretation: James Walton's personality is subjected to this. Lowry warns Cole of his flirtatious tendencies, and it is implied that he exploited Daly's intellect in the early days of the Callister company. However, Walton's colleagues (both women and men) seem to be comfortable around him, he genuinely loves his son and, as there is no hint that he is still married to Tommy's mother, being a 'player' is not necessarily a strike against the CEO. Furthermore, Walton shows a lot of nobility with his Heroic Sacrifice.
Walton probably had a friendship with Daly at some point in time, and likely still sees him as a friend. Walton does an affectionate gesture to Daly when showing Cole around, and the two bosses still work together quite well. There are only two scenes in which the real life Walton interacts with Daly and, while he certainly sounds abrasive, is completely right that the CTO needs to be more assertive when it comes to important things such as updating the game on time.
Complete Monster: Robert Daly is a sociopathic inventor who has created a special mod of the online game Infinity. By taking the DNA of his co-workers, Daly can create fully sapient digital clones in the game, which he uses to torture and mistreat to relieve all his frustrations. Endlessly abusing and humiliating them, Daly refuses to grant them any relief, at one point sealing Nanette Coles mouth to suffocate her and painfully transforming Shania Lowry into a monster when he wishes to make a point. Constantly putting them through endless pain and abuse, when one, Walton refused to play along, Daly got the DNA of his young son and threw the boy's clone out of the airlock with the threat he'd revive him and torture him worse if Walton didn't knuckle under. When the crew tries to escape, Daly vows to torture them even worse than before, starting with Walton's son, threatening how his punishment will be "biblical".
Critical Research Failure: While the tech featured in Black Mirror has never been hard sci-fi, it usually tries to stay somewhat within the realm of possibility. In this episode, however, Daly possesses a machine that can reproduce someone's personality and memories from their D.N.A., which is... not how D.N.A. works.
To say nothing of the ending where A group of AI are able to move into a 3D representation of a patch in their game world where the network firewall "detects the mod" they're using as a virus and strips *only that part of the program* away, then deposits the AI into a compatible program on the cloud as whole, equivalent objects. Even if the Network technology of the future has evolved to a point where that would be feasible, Infinity's network security must be abysmal if it's patching system essentially allows code injection from client users.
Originally, it was supposed to be explained that Daly was able to integrate their personalities and memories using technology similar to the grains from The Entire History of You, but Brooker felt that it resulted in too much exposition that hurt the episodes pacing so it ended up being handwaved in the episode itself.
Draco in Leather Pants: Unsurprisingly, Daly almost immediately attracted defenders claiming that his actions are completely justified, the crux of the argument being that his victims aren't real people—never mind them being real enough to think, feel pain, and even contact and interact with the outside world in a desperate bid to escape his torture.
Esoteric Happy Ending: As noted on the main page entry, Only the Leads Get a Happy Ending. But even setting aside the problems of their real life counterparts, the crew are still stuck forever in a created universe populated by G.I.F.T.-afflicted douchebags like Gamer691. The rules of their new existence free from Daly's mod, such as whether they're now capable of dying permanently, are also left unclear. Downplayed, in that none of those same douchebags have nearly as much power as Daly did and, as shown, the crew can just leave if things get threatening.
Another implication bordering on Fridge Horror is that the lead designer and key figure of the company that made the Infinty game is dead, which makes the in-universe future of Infinity very uncertain. Even without that in mind, how long would it take for the game to be inevitably rewritten or shut down, erasing the whole crew from existence in the process?
It's unlikely that the Infinity game as a whole is at risk. If the episode is anything to go off, though Daly invented it, it seemed like Dudani and the other programmers were the ones actively coding everything. Additionally, considering how large the office is, it's unlikely that Infinity is Callister's only source of revenue even if it's their most popular game.
Nanette mistakenly calls Daly's favorite show Space Force. Months later, in real life, former White House resident Donald Trump proposed a new branch of the United States military which he called the "Space Force". Even funnier is that Greg Daniels (who is a frequent collaborator of Michael Schur's, who made "Nosedive") created a Netflix original series named Space Force.
In Game Night, Jesse Plemons ends up playing a quiet loner with a creepy demeanor who is just outside of the main group which includes Billy Magnussen's cool guy, and the movie reveals partway through that a lot of the realistic turmoil the main group went through was orchestrated by Plemons' character as a game.
The revelation that Daly broke Walton by flushing his son Tommy out of an airlock whilst forcing him to watch. Even if they are only digital copies, it's still monstrous. The fact that he threatens to do so many times more, in even worse ways, if Walton steps out of line only cements it.
Alternatively, you could argue that Daly crossed it even earlier when he turned Gillian and Shania into giant insectmonsters.
An interesting debate, because he almost certainly crossed it the moment he decided to lock digital copies of his coworkers' minds into a modified video game for his personal amusement as revenge for perceived slights, but we don't really understand the depths of what he's done until partway through the episode.
Narm Charm: The whole "stealing my pussy is a red line" thing was utterly hilarious, but then wouldn't you be upset if you could no longer pee, poop, or masturbate? Also maybe justified by Nanette's subconscious forcing Skewed Priorities on her as a coping mechanism for her nightmarish situation.
One-Scene Wonder: A hilarious cameo by Aaron Paul as a Jerkass player who thinks the newly freed ship is just more players screwing him around in an attempt to trade resources.
The Woobie: Anyone trapped in Daly's Infinity mod.