I'd have to through my games in order to properly recall a really tough final boss challenge....but the only one that springs to mind has to be the final (Gear fight) boss in Xenogears. It was hella tough keeping those frames in nominal working order while attempting any form of attack. The damage this guy dealt was insane compared to what you were capable of throwing back his way.
Nightmare, while not a final boss, was the toughest challenge from Devil May Cry IMHO, simply because of that cheesy "you hit me, so I've gotta hit you at the same time" bs I've come to know and love (??) from most Capcom games by this point.
Zeromus was tough?? When did I miss that memo?? The way I look at it:
Kain jumps to minimize damage.
Rosa heals when necessary.
Cecil backs up Rosa, only attacking when the party is near full health.
Rydia summons.
Edge just throws out your old junk for heavy damage.
I'll be realistic here and admit that the Big Bang did hinder a lot of potential attacking strategies, but there were holes in his defense you could exploit if you had the HP to survive.
Mega Man 7: No arguements here. Moving on.
MegaMan X: Funny you should mention this game. I just played it recently, and while I may no longer have the reflexes from my SNES days, I didn't think he was all that tough. Only real issue here is the damage ratio you take from direct contact from Sigma....even with the armor upgrade, it hurts....a lot.
A pattern has appeared. Command??
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Sigma's dog: Before battle, charge your weapon to its full extent. Immediately after Sigma's speech is finished, perform a half-jump and release the shot. A level 2 or 3 charge knocks the pooch off its heels and gives you breathing room. Anyway, run to the left wall, climb and stay until the dog gives you some distance....then drop and fire another charged blast. If he hugs the wall and blows the fire column beneath you, jump out and fire once you land.
Sometimes, the dog will line himself directly underneath, so you may want to weave towards the wall in mid-air to regain your lost footing, or if the dog is far enough away, fire your shot. By this time, ol pound poochie is mighty offended that you won't come and play with him, so he decides to pounce back and forth along the walls until you has you in his jaws. Just slide down and fire when you have a clean charge shot waiting to bust his face wide open. Hopefully you won't take too much damage.
Sigma - Jedi Knight wannabe: Depending on where you start, you can take a single shot (charged or not)....if you're too close to risk it, don't bother. After you fire, immediately dash in the opposite direction and scale the wall while charging. Sigma will probably wait it out a few seconds before:
- Firing small bullets out his big ol' Popeye-lookin' head,
- Sidle up real cozy like to the wall you're dry humpin', or
- Make like his dog and jump for the Beggin Strips hangin' outta your ass.
Don't sweat the bullets. They can't touch you if you're high enough.
If he jumps, stay on your wall until he makes his second jump away from you....drop and fire in midair to tag him. If timed right, he should flash just long enough to where you can get off a single uncharged shot in his face when he drops from the final jump before you ascend the wall again. Keep on the same wall if he employs this method of attack.
If he shimmies up to the wall, he will make a series of wall jumps to where he will inevitably meet you in your hidey hole. Once he finishes his first jump, drop and fire, then immediately dash to the other side and start climbing....there you wait for Sigma's next setup. Repeat until he drops enough weight to look like that creepy crystal skull from the "House" movies.
Sigma - Anubis: Whoo-boy. It's hella tough getting through here without taking heavy damage, but it can be done. Set up shop dead center, then wait for one of three things:
- Head will blink, then follow up with a fireblast, stretching from left to right/right to left center screen.
- Head will blink, then follow up with a series of highly damaging disk attacks shooting in the pattern listed above. Tougher to dodge.
- One of the arms will shoot down towards you, dealing heavy damage or a straight kill depending on how it strikes. (Those spikes HURT.) Tough to anticipate, easy to dodge if you're on the ball.
No matter what attack Sigma starts with, you have to be aware of the lightning bolts coursing through both of his hands at all times. Even with your feet firmly planted on either platform/hand, you can take heavy damage here if you don't align yourself to the left or right of center, depending on your position and plan of attack.
If Sigma starts the flame breath, run to the opposite corner from where the breath originates, dodging the lightning along the way. You should be safe against the wall for a few moments until the breath subsides.
If Sigma starts the disk launching, stand
directly left or right underneath the central position, using Sigma's head as a center point. Depending on the direction the disks shoot, you need to wait until the dead last second after the disk in front of you falls to dash towards it and avoid the next in the series. This is the toughest part to consistently dodge, but it can be done. Example: if Sigma starts the disks on the left side, keep on the right side of his head until the last moment, then dash.
Keep in mind that only a fully charged X-Buster (hopefully you have the upgrade, or you're screwed) will damage Sigma's weak point. This is a fairly lengthy battle, and great patience is required to finish Sigma off for good. When he lowers either hand, jump onto it and ride to the top. You can only take one shot per ride when he does this, since the lightning comes fast behind you once hitting the apex of the flight path. Also, when you do fire, use a half-jump, but keep it floaty enough to where you slightly jump away from the active hand towards Sigma's face, in order to avoid the lightning and prevent slamming headfirst into Sigma, causing massive damage.
Granted, I may not have my old skills, but I used this method long ago, and at my peak....I managed to beat him using only one energy tank as a last resort.

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TMNT 4: Was that the arcade game?? Or the SNES version of Turtles in Time?? Super Shredder was a cakewalk on the SNES version....it's been awhile, but if the arcade version is exactly the same....then he shouldn't be any problem for me as well. Though that ray that turned you into a turtle baby and killed your credits was kinda cheesy.
Final Fantasy VII: Umm....funny thing. I had a really easy time on Emerald, while Khao walked all over Ruby....but it was so long ago I barely remember anything about it, except for you should go into battle against Ruby with two of your three party members already deceased. Khao might remember more about this than I do, lol.
Never played MDK2 or any of the Romancing SaGa games, so I have no clue there.... =X
Bantam13
--Throws it down old school style.