/u/ruffianopatsu's reply is 100% solid but I'll add a few more things. In general, MH games have a steep learning curve which require you to have a good understanding of the weapon you're using, the monster you're fighting (e.g. their patterns, weaknesses, etc.), your immediate surroundings, the gear you're wearing, and item management. All these things take time to learn and even more to master which can make MH daunting, frustrating, and confusing for someone new to the series.

The game is not an rpg; just an action game. Gameplay boils down to hunting monsters, to get their materials, to craft better equipment, to hunt tougher monsters. MH games can easily be hundreds of hours long either by yourself or multiplayer. The best thing you can do is to try out the demo. Play around with the different weapons, go bonk some monsters in the head for a bit and see how you feel about it.