There are two ways to look at Monster Hunter: World - a sport, and a singleplayer campaign. MHW might be one of the best sports out there to play with friends, but I'm a singleplayer gamer, and as always, I'll approach it from that perspective.
MHW introduces multiple hub worlds. While there are some open areas, there are also many linear levels with criss-crossing paths and a ton of verticality. It can be confusing at times, but I dig that feeling of being lost, and finding your way out of it. Learning the levels is also required over the longer term. Some of these new levels are utterly gorgeous, while others feel more pedestrian albeit still well done. There's definitely an inconsistency with the level design, although great overall. Of course, it's only skin deep, you'll not find any environmental storytelling here.
As the title suggests, MHW is very much focused on one thing - monster hunting. As such it's mostly a set of boss fights with formidable monsters, with some filler enemies thrown in here or there. The campaign does have a narrative and some bespoke missions, but they always seem to be overshadowed by the boss fights. The narrative itself is alright - a pretty formulaic tale, though with some great moments throughout.
But first, of course, it does have RPG elements, where as you learn, you get to craft better equipment, learn new skills to take on ever more challenging monsters. All of this works really well, and is well balanced. There's definitely a grind involved, which can be a bit time consuming for singleplayer gamers.
So, about the monster boss fights then, really the centrepiece of the game. These monsters are incredibly well designed, with brutal AI moves. The monster designs are highly creative with staggering variety, and most of their moves are as bizarre as they are smoothly animated. At the same time, they are fair, and always signal their moves before making them. Taking them down, then, becomes a matter of timing, pattern recognition, and patience. For skilled MHW players, it's going to be easy going. However, for simply singleplayer gamers, some of these boss fights can be matter of attrition. They move to different locations, spring new moves over the battle, so there's a lot of tracking and learning involved. It took me 30 minutes to take down some bosses, but it never quite got repetitive or frustrating. There are plenty of tools to keep things flowing, with potions, limited respawn, and even a way to call for help to more experienced players in the world. As such games go, MHW does a much better job at accessibility than, say, Dark Souls. Overall, the core gameplay loop if MHW is highly successful, balancing difficulty with accessibility nicely, though still not for everyone.
The singleplayer campaign isn't very long at all, and much of it is just boss fighting anyway. Beyond this, there's a ton of end game content, and this is where the sport aspect of the game kicks in. Unfortunately, I don't really have the motivation to grind for dozens of hours and take out the insanely difficult end game bosses. So I called it quits shortly after the main singleplayer campaign ended. For singleplayer gamers, I'd say MHW is a pretty good experience, while for those who love a long-term challenge, MHW is probably essential play.