First time I tried Omega Pirate on hard i got him to half health... that was after not playing the game for 3 months... So really I wouldnt consider him the hardest...
I havent really faced anything that I would consider "hard" But the Boss that gave me the most trouble was Sephiroth from KH. But, its all about knowing what he does. He has like... 5 different stages. first he just does the slash and the firewall. Then he goes on to sin harvest. Then off into his beserk mad ground to aerial combo. Then the meteor attack, and those anoyying black orbs while he does the spinning attack right after teleport. Once you see all his stages, he's cake.
For some weird reason I had trouble with Kurt Zisa... o.O
Try beating any of the bosses in Super Metroid with a keyboard... now THATS hard... since the keyboard cannot read 2 keys at once... you gotta be able to jump then let go then shot in about a split second... Hard shiz...
