Eternal is easily the best FPS ever made. Name something better. It'll be funny.
Even if I'm only allowed to reference other Doom games, this one is still easy.
Doom 2016.
Doom Eternal is basically Doom 2016, but bigger. The problem is that the "but bigger" is usually poorly thought out and generally results in more confused gameplay and design that clashes with itself in horrible ways. Doom 2016 had a lot of nuance in it's gameplay that was very interesting if you scratched the surface just a little. Eternal added so much extra stuff that the nuance of 2016 largely got trampled over. They also tried to fix a bunch of issues from 2016 but their fixes just ended up making the problems worse and reducing/eliminating the gameplay depth.
For example, Doom 2016 had a problem where people wouldn't use a variety of weapons and the Gauss was considered overpowered. The correct way to fix this problem is to implement enemy weapon weaknesses (which they did), but they also overcorrected by massively reducing ammo counts. For unrelated reasons, they also gave us access to 2 throwable grenades instead of one, both on separate cooldowns, and both quite powerful. This has serious knock on effects for the rest of the game. Instead of allowing players to properly manage resources and make tradeoffs to expend rarer resources for easier kills (the entire point of ammo in every game), the ammo counts are so low that instead players are supposed to always save specific weapons for specific enemies, in a sort of boring paper-rock-scissors gameplay, while they run around waiting for their cooldowns to recharge. Worse, because the player is very likely to end every fight with no/low ammo (or run out midway through), they needed to give them a reliable way to refill during and between battles, which is why they implemented chainsaw recharging. And because it recharges, there was no need to intelligently place chainsaw fuel anymore. This completely eliminated one of the most interesting early-game mechanics of 2016, which allowed you to trade ammo reliability for a big, instant kill. If I had 3 chainsaw pips, I could kill 3 imps, which would fully restock all of my ammo 3 times. Or, I could kill 1 hell knight, which would remove a major early game threat, but only allow me to refill once. Even more interesting, to take on larger enemies, I needed 4 pips, meaning I had to upgrade my ammo using argent cells, allowing for a level of build depth - I can upgrade health/armour to focus on raw survivability, or gain the ability to instant-kill larger enemies like mancubi with the chainsaw, which is a good tradeoff. Because of the extremely limited ammo and recharging chainsaw of Eternal, all of this is gone completely. Now, instead, you're supposed to mindlessly run around arenas looking for imps, with the chainsaw being relegated to "press X on an imp occasionally in combat when you're running low" and having absolutely no depth whatsoever, and encounters are designed in such a way that they are constantly flooding the arena with small enemies, to stop you running out of ammo completely, and the ammo upgrade doesn't even give you more max chainsaw ammo anymore, eliminating the ammo upgrade for larger enemies gameplay entirely. What was a flawed but interesting system is now a slightly less flawed but much more boring system. Many aspects of Eternal are like this.
This is not mentioning the other tacked-on and not-well-thought-out gameplay elements like the overreliance of platforming sections, the extremely cringey player dialogue (especially the scene where he yells "rip and tear" repeatedly and it just sounds overly edgy), the confused art-style mixing surreal and cartoony elements with mundane looking bases and industrial areas, the general instability and performance issues related to Denuvo on release, the severely lackluster soundtrack, or any of the other big issues with the game that aren't present in the previous entry.
Eternal has some interesting enemy designs in it, and it does make some genuine improvements to the formula. I can understand why people like it, and the expanded enemy roster specifically can make it feel like "Doom 2016 but better" when it's firing on all cylinders. However, it's brought down by it hyperfocus on trying to enforce the developers vision - that is, one of players constantly switching weapons, using abilities constantly, and generally playing it in one specific (albeit difficult) way, which undermined a lot of the other areas of gameplay. Eternal is pretty fun, I just wish it didn't feel so soulless on account of pushing everything into the same direction of "run around and shoot shit". For all of Doom Eternals claims about "play your way" and "use what you find", there's really only one way to play it. Doom 2016 isn't exactly an RPG masterpiece, but there was some interesting strategy to be had under the hood, much of which I believe went right over players heads because they were too distracted by the gorey combat, the tight presentation and the general badassery of it.
When you consider the complexity of it's gameplay (or lack thereof), Doom 2016 somehow manages to be a lot more than the sum of it's parts. Doom Eternal, on the other hand, feels very hollow and lackluster after a while despite having a lot more mechanics and enemies. I got so bored I couldn't even finish the DLCs
What's even better is it was made in a time where difficult games and not-made-for-controller games were verboten.
Really? 2021 was the height of the modern boomer shooter craze. While this was a triple A release and most boomer shooters of the time were indie games, it was clear and obvious that the demand was there (especially with the success of the previous title), making it a pretty safe bet that it would do well. The real risk was releasing a Doom game in 2016 to a market saturated by hero shooters and multiplayer-focused games to an audience of oldschool gamers who were skeptical of it from day one, especially when id was largely know at the time for their lackluster previous titles. Doom Eternal is, if anything, a safe/conservative sequel.