Any boss in The King of Fighters saga, especially Rugal.
Aries from GoW.... he wasn't that hard, but I got in a slump. I was so pissed with the weapon change and his counters that I wasn't thinking straight... I was just dying out here for hours.
Then my brother forced me to take a break(his console). When I come back I just beat the crap out of Aries in the second try(what make more pissed since he wasn't that hard).
Either Ruby or Emerald Weapon from FF7. Cloud was such a bad-ass character back in the day.
I have to say that the The Harvester from Dragon Age(one of the expansions) was the hardest...hours and hours of gameplay went into defeating that ugly mofo...and the first part wasn't even that hard...I mean getting rid of the main body is not that difficult....but dealing with the second part, where all sorts of tough skeletons appear...
Super Contra final boss or Ruby Weapon from FF7.
Ruby Weapon was just...
I found Ozma in Final Fantasy IX to be tough.
However if you did the sidequest before hand, Doomsday (one of his toughest moves) can actually benefit you, if you use equipment that absorbs shadow.
The move that gives you the status effects made it awful.
Both the weapons in Final Fantasy VIII took me a while as well. With Omega, the patterned move set meant it was more a case of just healing at the right time, and quick enough between attacks.
... Luckily Pheonix rescued me in all three of those fights.
I also found Onox's dragon form at the end of The Legend of Zelda: Oracle of Seasons tough, but I was 9 during my first playthrough. Although he's supposed to be one of the hardest Zelda bosses.
I don't know actually... Maybe Raam from gears of war 1 on insane difficulty when I was like 13 or something, it'd be so easy now, I just gotta find the disk.
Jimpachi from tekken 5. I hate him!
without a doubt the omega weapon on FFXII or yiazmat (more for the time than anything else)
those two are not only rediculously difficult (even for a level 99 party) but on FFxii its harder to make your team dominant like the older games (you could basically build an invincible team in FF7, 8 or 10) but you would think you could at least beat some of these bosses at level 99 unless my brothers party just wasnt built right
personally i never played ffxii that much but, i did try to beat these two bosses with my brothers party, it wasnt happening
---------- Post added at 09:47 AM ---------- Previous post was at 09:34 AM ----------
i just used the attacks with freya (dragon crest) amarants chaakra ability and zidanes dyne attack to take 9999 every chance i could and spammed eiko's pheonix summoning
and i barely won but im sure if my level would have been higher than 67 the fight may have been a bit easier, the hardest thing about ozma is that his attacks are so random, so depending on what attack pattern he has he is either beatable or unbeatable, regardless of what you do
about omega in ffVIII this guy was REALLY hard, i just spammed the lion heart, the angelo limit break with rinoa, and tried to use ever GF that i had and i was also bailed out by the phoenix flame, the amazing thing about phoenix in FFVIII is that you can only cast it with a phoenix pinion , and then later in the fight phoenix may or may not appear on his own so after omega wiped my party out with that mageto flame attack or whatever its called, i saw the drop and the phoenix flame
i was amazed , and i used a megalixer a her drink or two and wound up winning the fight, once again by the skin of my teeth