I can't even begin to believe how long this post is.
However, I will add the once boss I have never been able to beat (And I have been gaming since before, and through, the eight bit Nintendo): In the game Jedi Knight II, on Jedi Master, I have been unable to take down Desann.
He is a God.
I set up five droids, five turrets, and force pushed him to the ground (hacking away when he was down) multiple times, and was yet unable to beat him. I gave up after about five hours of trying to take him down, neither actions I do often (And yes, I did use the power up thing in the middle. It still didn't work.)
Just try it! If you can make it through the game on that difficulty (Which I can proudly say I did! =D) then I'd like to see you beat him. If you can, my hats off to you.
Though, I wonder now, if I should've given it a second go?