[All Time Hardest Boss]

I fucking hated fighting King Blue in Viewtiful Joe on Super V Rated. He was cake on normal mode but on super V he gets an ass-load more hit points that just takes forever to get down. All attacks hit you for 4x damage, which means 4 hearts for every hit, 8 for certain attacks (which is more than half your health). It's also to screw up hitting him the one time he's vulnerable, and if you do, that means a whole nother round of attacks to dodge. He's really not that bad when you get his pattern down, but the fight is just so damn long. There's a follow-up fight after that one too that isn't nearly as hard, but if you get game over you'll have to fight King again.

EDIT: and Akuma from Super Street Fighter II Turbo arcade was fucking impossible. I would pay to see someone beat him on a machine.

[All Time Hardest Boss]

At this point, I REALLY don't want to check if I've already posted here...

The hardest, most annoying boss in recent memory is Dr. Wily from MM7. Maybe I just missed a secret weakness, but it's nigh-impossible to dodge his attacks in his final phase. His super-powered attack.

If he's out of your range, stand directly below him, wait for the balls to appear. They move in two thrusts, one that moves in your general direction and one that moves to the end of the screen. The moment they move for the first time, slide to the left or right, whichever side you have more room. And in one great leap, jump over all four of them. Try to do it at the last possible second, it's kind of tricky. If you have take a hit, take the lightning (yellow) one. That does the least amount of damage.

If he IS in range, hit him with a charge shot and quickly follow up with a shot of Thunder Bolt (You'll probably want to pick it from the menu). He'll be shocked, but won't do any damage. It'll cancel the normal energy ball attack and he'll two lightning orbs downwards, which is very easy to jump over.

If you're feeling lucky, you can try using Freeze Cracker when he's out of range, but this usually messes up your rythm and you'll have a much harder time dodging the energy balls. I also hear Wild Coil does a decent amount of damege but I didn't notice anything. Just stick to charge shots.

Any way you slice it, it's going to be a very hard, very tedious fight. There's really no way around it. Be sure to bring a full stock of E-Tanks and don't start using them unless you're confident that you have a chance of beating him.