Am I distinguished mentally-challenged or is the boss of chapter 3 impossible to beat?
It's actually a very easy boss. Use the bow. When he's facing you, charge the bow to max and shoot him in the face. On his way towards you he'll likely do some crazy attack that feels out of Panzer Dragoon, but unlike Panzer, you can't shoot all of those orbs down. So instead of attempting to dodge all of them like normal, run forward, hug the edge, so you'll have run by all of them by the time he gets to other side. When he's turning around, charge, release. When he does the electricity attack stay as far as possible. When he turns around, charge, release.
Whenever he's towards YOU, you go should be going towards HIM, that way you can prepare for his attacks and dodge them, and also prepare to charge your bow as he turns around.