General Raam Gears of war

Ganadorf in Zelda Ocarina of Time can be frustrating if your not spot on with your aiming when using the arrows to bring him down in order to slash him several times. That is after of course the fireball tennis you get into with him which requires decent timing. And then its repeat over and over again. Yeah and falling of the block doesn't help either which means You have a big climb to contend with and he will be at the top waiting for you.

100% agree haha!

batman return of the joker for nes, i swear that the joker is impossible to beat, at least legit in consoloe and not by using save state in emulators

dracula from castelvania dracula x, he is really hard but once you see the pattern its possible to beat him
https://www.youtube.com/watch?v=O9FX95aFyr4

I defeated him with one Omnislash :D.

Radec from Killzone 2 on elite difficulty.

I'd say that the boss of Cave Story's Hell was pretty damn difficult...the entire end section of that game is just brutal and wonderful

I can't remember... xD
Instead of telling you the hardest boss I've ever faced I'll just tell you the hardest bosses I've fought in the last months =p

Black Heart Noire - Hyperdimension Neptunia Re;Birth 1
Killachine (first battle) - Hyperdimension Neptunia Re;Birth 1

These battles were insane (and unexpected) difficulty spikes but it was so rewarding when I defeated each of them.

Back in the '90, I used to think Ganon in A Link to the Past was impossible. Literally, I didn't think it could be done. Until of course, I beat him on the GBA in the 2000s. Nowadays, he's no problem.

Ignoring old-school, in modern gaming there's not really such a thing as a hard boss. I mean, there's hard bosses, but no 'hard' bosses. The last boss I seriously had a problem with was the Nightmare X in Metroid Fusion.

talking about most recent games, the secret bosses in xenoblade for wii are almost impossible, i have defeated 2 so far of the 5 there are in the game

i defeated Despotic Arsene and Final Marcus, but Ancient Daedala, Blizzard Belgazas and Avalanche Abaasy are almost impossible eventhough you reach maxium level

i a have watched videos on youtube to figure out how to beat them like Deadala but the boss still is way to hard
just look at this fucker, i am not even near enough him to attack and he pinpoints you from any point(even if you go from behind he will notice) at certain distance and will throw a laser beam that deals about 90% the life anergy of one of your comrades
https://www.youtube.com/watch?v=se5MT49R4J4