I'm not going to join in on the debate about whether there should have been a tutorial or more explanations or not in the demo because I can see both sides of the argument, but I will say one of the really great things about Monster Hunter is learning new things all the time in it.
Like the poster above said, 60 hours into the game and he just learned about a very basic thing. You can look at that both ways, annoying that he didn't know that for so long, but also amazing that after so long playing the game he's still learning new things.
40 hours in, 100 hours in, 300 hours into Tri and I was still learning new things about the game. To me, it really made the game stay fresh and kept showing off the amazing depth this series really has.
There are hundreds of items in the game, the demo has like 30-40 or something like that. Would you really want it to bog you down and explain them all? I think the the demo just wants you to go in, and figure things out for yourself. That's really the fun part about monster hunter.
You watch the video I quoted and I guarantee you the next time that guy plays, he'll be better, then the next time even better and his hunting skill will grow so exponentially that that is the real 'leveling' up system of monster hunter. It's player skill, player knowledge of the weapon, player knowledge of the monster, and player knowledge of the game itself. There's no +1 level of this or that. But if you watch new people play, or you're a new person yourself, be aware of all the different aspects of the fight you are getting better at each time you play. You don't have to kill the monster on your 2nd or 3rd or even 5th try, but I guarantee you're getting to be a better hunter. A better Monster Hunter!!!