It's a game where you hunt monsters.
No, I'm serious. The Monster Hunter games realize this fantasy and this milieu in a way that very few big AAA titles realize their fantasy and milieu. The action-adventure and action-RPG design vocabularies are pretty calcified, and a lot of those games have themes but those theme are loosely draped over a skeleton that's structurally the same as a lot of other games.
In Monster Hunter, you hunt monsters, meaning that almost nothing about the game is the way that it is just because of genre expectations. Monsters are huge and threatening, and fighting them is a protracted battle; it's a game made almost entirely out of intricately designed boss fights. But your entire kit of affordances is designed around this, intended for fighting giant monsters.
Preparation is a big component of hunts, from buffing yourself to carrying traps and other anti-monster items to equipping armor that specifically negates a given monster's tricks. It's a game about using resourcefulness and clever tactics to take down enemies that are much stronger than you.
At the center of all this are the monsters themselves. A huge part of the appeal of the series is just in the creature designs, which at their best are incredibly cool but also just thoughtfully in conversation with everything from fantasy tropes to paleoart. Anjanath is a great example: a fire-breathing t-rex could have been kind of trite and obvious, but they gave it a vulture-like feather pattern and a sort of permanent fire-sneezing hay fever.
The monsters have behaviors, ecologies, intentions, roles. They're the most reactive, interactive, and richly designed enemies I've ever seen in an action game. Because an individual monster is the centerpiece of an entire hunt, they can have all of these systems running through them making them seem more alive than any conventional action game boss.
Cut off Rathian's poisonous tail and it can't hit you with it any more. Fire a burst of stunning pellets right into the monster's eye and it'll launch itself; do this with the right timing, and it'll smack its head right into a wall. Jump onto the monster from a tall ledge and you can ride it like a buckling bull, exploiting the fact that it's trying to throw you off, sometimes by swinging its own body at walls to try and catch you.
So these fights don't feel like straightforward damage races, they're not a game of trading blows, of dodge-hit-dodge. You have goals, you have ideas, you have tactics you're brewing up as you fight. You're building up towards things: getting the monster stunned or trapped, breaking one of its body parts. Sometimes you're just trying to let an angry and aggressive monster tire itself out without getting hit; in this game, the monsters themselves also have a stamina meter, of sorts.
This is all tied together by the other major unique thing about Monster Hunter, the weapons. The fourteen weapon types in MH are essentially the series' character classes; each one has completely unique affordances and a totally different playstyle. What makes them brilliant is that they are all powerful in their own ways, and they all allow for a great deal of skill expression... but it's different flavors and types of skill expression. Some weapons have resources that you manage, or different states they can move between. Some weapons have a very broad toolkit, letting you choose between different approaches based on the moment. Some weapons, conversely, are extremely good at doing one thing, and their utility blooms from that one thing. Some weapons emphasize uptime, letting you chip away at the monster bit by bit as long as you can continue to avoid being hit; others emphasize knowing the monster's openings and picking your spot, giving you big chunks of damage as a reward.
I really, really love those games, and I think they only seem daunting. Monster Hunter World is no more complicated than Elden Ring or God of War, it's just very different. It refuses to be like everything else, and so it has that extra learning curve because you can't always rely on familiarity. Even the game's basic loop is different, with a mission-based structure that's unlike the contiguous world of a typical action-RPG. But coming to grips with it has been intensely rewarding for me, the ind of rewarding I've only gotten from a handful of other games; games like Dark Souls or Symphony of the Night or other genre touchstones. Except MH isn't a genre touchstone; it's almost inimitable. I can count on one hand the number of imitations and I could be missing three fingers.
You really should try it if you like action games at all. It's honestly never been a better time to get into World or Rise.