Before we can explore what makes a great video game villain, though, we'll need to define what "villain" even means in this context. Is Berzerk's Evil Otto a villain? Are the ghosts in Pac-Man? The bonus point saucers from Space Invaders and Asteroids? Flexible as I am with the storytelling potential of early games, even I would say "no" to all these. Enemies, sure - their entire purpose is to attack and/or be attacked by the player, which separates them from non-enemy obstacles like the titular Asteroids. It seems unlikely that any of them are responsible for the circumstances the players have found themselves in: they could be better described as foot soldiers (the rank-and-file Space Invaders), monsters (the Pac-Man ghosts, which even names them as such in early iterations), and possibly henchmen (Evil Otto pursues the player with purpose and direction the Berzerk robots lack, but almost certainly didn't build the maze himself and seems, if anything, to be a mildly anthropomorphized version of Rover from The Prisoner). Even Donkey Kong himself probably shouldn't be considered any more responsible for his actions than his cinematic inspiration and namesake. (Mario, on the other hand, has no such excuse for his one-time heel turn in Donkey Kong Jr.) In this era, antagonists with intention were more likely to show up on home computers than consoles, with early RPGs leaning heavily into standard fantasy "Dark Lord" tropes, but even then, the villains' interactions with the player were largely indirect: they had created the dungeon, or summoned the monsters, or scared off all the town inhabitants
so the developers wouldn't have to worry about NPCs to establish the magnitude of the threat. The characterization of the villain, then, was a conveyed through setting an gameplay - an early example of environmental storytelling. As text adventures developed, they were able to gradually provide their villains more depth, but on the console side, characterization was still enemy and level design, with the occasional smattering of text. These characters' staying power showcases the effectiveness of this approach, which allowed for a surprising amount of subtlety. Dr. Wily builds a number of robots similar to Mega Man, establishing him as an antithesis of our character's creator (and thus, of the player) long before we face off with him. Bowser (or "King Koopa" as he was better known at the time) is a giant turtle, built up by not only the enemies in Super Mario Bros., but in the previous Mario Bros.- turtles, evidently being plumbers' arch-nemeses.
Not that every villain has to have such lofty ambitions, of course. Plenty of them merely want to rule the world/universe/crime syndicate... or just watch it burn. (Funny how these apparently contradictory motives seem to require identical methods.) This doesn't need much in the way of setup, and using historical examples or fictionalized versions makes them even more recognizable. Real-world fascists idolize the Romans from which they take their name, so referencing the Roman Empire directly conveys the weight not only of that historical precedent, but all those who have tried to emulate it. In some games, even today, megalomania is enough, and we can rely on characterization through gameplay. But this rarely makes for a memorable or compelling villain - even the ones whose motives are simple and basic stand out by how they go about achieving their goals, and (specific to this medium) how the player factors into this. Players, after all, gonna do what they've gotta do to progress in the game, and some villains take advantage of that to eliminate competition or set the stage for whatever their plans may be. Metal Gear is again an example here, but I'm particularly thinking of Max Payne 3, which combines the protagonist's tendency towards violent combat (and the player needing to do so to, y'know... play the game) with the underlying assumptions of the "White Savior" trope that runs through most Western media, particularly action-heavy stories. In short, Max Payne, as the white outsider in Brazil, is used by the villain to remove the obstacles (which, to be sure, are also very bad guys) in his way. There is an argument that forcing the player to stick with the narrative (there's no other choice but the play through as written or just stop playing the game) blunts the intended message, but as long as games continue to be made that treat violence as an unquestioned good, there will be a place for titles that do question to whose ends that violence serves. Again, this is something that can feature in other media, but is uniquely suited to the game experience. We were there, we did all those things, and now we find out that it didn't matter in the way we wanted? Without deft handling, this can feel like a cruel trick, and make the player feel like all their time to this point has been wasted. But when done well, it can add shades to the game's contextual and moral palate. As to how successful this can be, that's entirely up to the player and what they take away. I've already named some of my favorites, and you're probably thinking of your own... or ones that pissed you off in trying it.
Finally, there is the presentation of the villains themselves, including character design and, after a certain point, voice acting. This can make a huge difference in whether a villain is memorable or not, and needs to be consistent with the tone and themes of the game. Metal Gear Solid frequently deals with themes of identity and how we reconcile who we are with who we're told we are, so a number of the villains are literally modeled after the protagonist. Others mirror the main character's past or role. In games like Wolfenstein, which operate on a level of over-the-top camp, the villains are broad grotesque caricatures, hammily acted and often given goofy gimmicks. They don't need to reflect the protagonist at all, simply give the audience a target at which to direct their ire. For characters without voice acting, design becomes all the more important, again drawing a line in common with comics (pun... possibly intended). The requirements are still the same, though, consistency with the tone of the work as a whole, and with the themes the game embodies. In a real sense, after all, the villain is the game, and we spend the entire time dealing with them and working our way up to them. And the time we spend leading up to our big confrontations may be an even great factor than what we find when we get there. It's rare for anyone to ever say "it was a boring game, but a great bad guy." They're one and the same, after all. And when we say "we love to hate" a villain, what we really mean is that we loved the time we spent getting to them, we loved undoing their plans and defeating their underlings. That's what makes video game villains so special, and I'm glad we have the scoundrels to face off against.
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