I found the quickest and easiest way to defeat the 1st boss is this:
a) Lure him against one of the long walls (from a distance of course)
b) As he nears, do a wall run over him.
c) When above him (or near) do a Y-button strike, block-roll, and leg it.
d) Repeat.
You can defeat him unscathed using this method, and because you're both against a wall you get a good camera view.
Yes, I've improved greatly since my whinge

Here's how I defeated the next two bosses (untouched)
2nd boss (Samurai horsemen):
Many guides tell you to defeat all the mages first (floating magician characters). Forget that.
a) Stay at your end of the bridge facing the horseman as he charges.
b) Hold the weapon charge-up button.
c) Let it go when he's close. You'll strike through him out the other side.
d) Bash the Y-button a few times to strike him.
e) Dodge out the way. He'll counter attack.
f) Jump around until you've got the original position back (you at one end, him the other)
g) Repeat.
Ignore the mages, they'll fire off shots at you, but if you keep at one end it's easy to dodge them.
3rd boss (big fat electric guy on airship)
On your first encounter you'll get whipped and wonder how on earth to defeat him. Try this:
a) Run around him at a distance to dodge his 5 blasts.
b) As soon as he's shot off his last he'll recharge (weapon upright, glowing blue)
c) Run in there, jump-strike (Y-button)
d) Strike from his other side once. Be quick.
e) Block-roll away. He'll lean back to counter you. Find the distance you are safe from the blow.
f) When he can't reach you he'll try and recharge. Guess what? Go in, strike him, and repeat c).
When you get this method right you'll finish him off with him ever getting another shot out. This is good because when he gets angry he'll be firing off like crazy. And you'll die.
What I've learnt from this game is that the bosses are fairly easy when you learn their routine. Hope these initial tips help.