The mechanics on the first boss ruined it.
A first boss should generally be more of a challenge than the average enemy, but not enough that you don't stand a good chance of defeating them on your first try. This draws you into the story, and gives you an idea of how you fight bosses. This boss was nigh impossible.
Firstly, the instant kill wall at the back. If you don't figure out the correct way to fight, you get knocked into it. If you do figure out the correct way, the boss suddenly stops responding to attacks (I hit him, he skips the fall down sequence, roars, I hit him again, he skips the fall down sequence and roars, then he spins at me till I hit the wall.) and forces you into it. An instant kill mechanic is not a good idea for a first boss.
The forceback mechanism. You are gradually forced back, in an unpredictable fashion, to the wall. If the enemy randomly decides to not drop dead when you attack them, then there is no possible way you can win. You can't dodge, jump, or anything.
The annoying bit before it. Whenever you die, you have to rekill that random guard, over and over. Annoying.
Anyway, this game is poorly designed. I'm sure with enough tries I would be lucky, and when I get his health down, he'll die. It will just be luck though. No special skill. You get in close, and slash three times with your sword. Then you charge hit him back.
Nothing I can do to effect this. I can dodge his attacks enough that I don't die of health loss. I can't get past him. So I stopped playing and gave you a three out of frustration.