Is there no indication of how well you're doing? No enemy health bar? Also, is there no way to target the enemy? Like the player in the video, I swung at air a lot of the time. I felt that I was fighting the camera as much as I was fighting the enemy.
This is pretty much one of the big points and appeals of the game. So no, no monster health bars or anything. As pokepal148 said... it's a learning experience. If you want the game to hold your hand, it just won't be the type of game for you.
Despite being a very fantasy based game with a lot of quirks and absurdity ( those massive weapons, the funny animations, sharpening a hammer(wat?), etc) I find monster hunter to be VERY realistic in terms of gameplay. If you're hunting a beast irl... it's not going to give any indication of how close you are in defeating it (aside for maybe flinching or limping, which the MH monsters do). Your actions aren't going to be perfect either. I find the awkward camera and long animations akin to the limitations of human movement. The game is a lot about learning, timing and strategy - knowing what is possible within your limitations and executing it properly.
As to the question about "locking on"... well... not exactly. If you press the L button the camera will center behind your hunter. In 3U there is a Target camera feature that you can turn on by touching the icon on the touch screen that looks like an icon of the boss monster you're fighting once it's spotted you. When you do that, now when you press L the camera will center on the monster. So it's not a true lock-on feature (as such a thing woudl go against the play style of monster hunter), but it helps immensely if you're having trouble keeping up with where the beastie is.
As other have said.. the demo is terrible as a demo for newcomers... it doesn't explain ANYTHING at all. It really is just essentially a weapons show for seasoned players. You can look through the demo's guide which will explain the controls a bit, but really, this demo just doesn't show off the game in a proper way to new players.
A great, rewarding game if you're willing to put the effort into learning it though. Especially fun with some buddies... I'd say drop all your preconceptions and give the real game a shot, but I'm already one of those crazies who's logged hundreds of hours on the previous game (even 7 on the demo so far). X3