The game is fairly challenging, some say it's "too" challenging.
The game lets you upgrade your gear, so you can out-gear the next areas of the game if it gets too hard.

It's definitely an awesome adventure, a feeling I haven't had with exploration/rpg games for a long time,

There is PvP, but it's very basic.

Bosses are a thing, and they are in the open world.

The crafting is exceptional, so is the building. Game supports 8 players on the same server I think, maybe more with mods, but it's kind of laggy atm with a lot of players.

Highly recommend playing with friends that live close to you, for best ping.