These are my top ten hardest bosses.
If your boss is not on here I have not played every game or different opinion

in no order


Dark Gaia not so bad once you get used to him but at first hes not fun.
Krool 64
Whiz Pig
Sigma in some versions.
Sepulcher first boss in Silent Hill 5.
Spark Mandrill without weakness.
Blast Hornest without wekness.
Majoras Wrath unless you have that mask.
Solaris very similar to Dark Gaia once you learn how hes not so bad but a pain in the start.
First phase Force Unleashed DarthVader the part where you have to get lucky to
even get to him.

I'm part of a circle of friends on YouTube who make these exact things- Countdowns on video games, such as hardest bosses, easiest bosses, and so on.

Mine are...
#10: Team Chaotix Robot Storm (Sonic Heroes)
#9: The Buebeam Trap (MegaMan 2)
#8: Princess Shroob (Mario and Luigi: Partners in Time)
#7: Vortigon (Chaos Faction)
#6: Junker (Mario and Luigi: Bowser's Inside Story)
#5: Metal Overlord (Sonci Heroes)
#4: Devil Doom (Shadow the Hedgehog)
#3: Copy Robot (MegaMan)
#2: Queen Larsa (Mushihisesema Futari)
#1: The Ultima Weapon (Final Fantasy VI)

Gruntilda from Banjo-Kazooie and Tooie where in my opinion, very hard unless you had cheats on. or if you are replaying it with only 5 health, it is IMPOSSIBLE!!!

I really don't think Krool was even a hard boss at all.

@ SarothCyngus: did you say Metal overload, Devil Doom, copy robot(Megaman), are hard?

But these were the easiest bosses I've ever seen(sorry if I made you mad).

I'll tell my hardest bosses:

#5Dr. wily(Megaman 7)
#4Nobunaga(onimusha in hard).
#3The final boss in Metal Slug Advance.
#2Freezeman(Fireman:incoming storm in normal not easy mode)Note:This is a flash game so you'll find it in the internet not in console.
#1Brain(Bomberman Max Red: Challenger), I've died more than 50 times to beat him.

the hardest bosses to me is

#1- king boo(luigis mansion)

#2-ganon( a link to the past)

#3-last boss in kirby nightmare in dreamland( not sure what the name of him is)

there are others, just can't name them all

Top Ten Hardest Boss' now that is a tough one cause I've played a pretty good bit of games growing up. Well let's start and this is in no particular order either that would just make it even harder.
1. Nemesis (Resident Evil 3)
2. Dracula (CastleVania)
3. Jason (Friday the 13th)
4. The Elite (Pokemon Stadium)
5. Bowser (Super Mario World)
6. Many Boss' from MegaMan Series
7. The last Colossus (Shadow of Colossus)
8. The Chicago Bears (Tecmo Super Bowl)
9. Three Headed Dog (Parasite Eve)
10. Dr. Robotnik (Sonic the Hedgehog Series)

I can't remember many bosses off the top of my head but both Safer Sephiroth & Rapthorne's second form were pretty tough for me although Sephitorh was a tad bit easier.

#10 Alec Trevelyan (Goldeneye 007) The level is a boss, but everything about the level, from the minions to the turrets, are a big pain.
#9 Dracula (CastleVania) A big pain when you first fight him. Even if you get his pattern down, you will still lose at least once to his second form every playthrough.
#8 Dr. Robotonik (Sonic the Hedgehog 2) He has a predictable pattern, but you will eventually screw up a jump or you'll be too slow and face his wrath.
#7 Ridley (Super Metroid) He'll just keep breathing fire and whipping you with his tail until you die. Simple.
#6 Burner Man (Mega Man & Bass) When you finally reach him, even with his weakness, GET READY TO LOSE! He's insane.
#5 The HAG 1 (Banjo-Tooie) From broom to TANK. Nice going, Grunty.
#4 Elecman without weakness (Mega Man) YOU WILL DIE!
#3 Wizpig (Diddy Kong Racing) If you miss a speed boost or fall in the water, you already lost.
#2 Wily Capsule (Mega Man 7) He's the reason why many people hate this game.
#1 Mike Tyson (Mike Tyson's Punch-Out) OHKO punches, lightning fast speed, and the ability to screw you up when you think he has a pattern. He's just HARD.

my top 10 in no particular order

Seymour Flux (Final Fantasy 10)
Sin (Final Fantasy 10)
Villager Hoarde's(Resident Evil 4)
Demonic Hellicopter (Shinobi)
Sephiroth (Kingdom Hearts)
Xemnas (Kingdom Hearts 2)
Ovan (Dot.Hack G.U. Vol.3)
Skeith (Dot.Hack Legend of the Twilight vol.1)
BIOLIZARD (Sonic Adventure 2 Battle)
Collossus (Demon Souls)

Hmmm..

1. Pandemonium Warden (Final Fantasy XI) Was too hard to beat, so he was cut from the game. (Difficulty Level: 10/10)
2. Absolute Virtue (Final Fantasy XI) Only beaten by some people. (Difficulty Level: 9/10)
3. Dustflier (Kingdom Hearts 358/2 Days) That guy is evil. EVIL. His attacks kill, and he can OHKO you with a certain attack. (Difficulty Level: 9/10)
4. Xion (Kingdom Hearts 358/2 Days) She is hard, unless you battle her with Roxas. (Difficulty Level: 7/10
5. Tiamat (Final Fantasy IX) Can blow you to bits with an attack called Jet Fire, and can absorb your strength and defense. (Difficulty Level: 6/10)
6. Dr. M (Sly 3: Honor Among Thieves) This guy is hard to hit, and he is brutal with his attacks. (Difficulty Level: 8/10)
7. Sephiroth (Kingdom Hearts II) Can prove to be a very difficult enemy without a high level and Ultima Weapon. (Difficulty Level: 8/10)
8. Sephiroth (Kingdom Hearts) See above. (Difficulty Level: 8/10)
9. Red (Pokemon Gold/Silver/Crystal) His pokemon are ALL over Level 80. That is evil. (Difficulty Level: 6/10)
10. Neo Exdeath (Final Fantasy V) This guy is a PAIN IN THE FREAKING ASS. (Difficulty Level: 9/10)

I have changed my mind.
Barthandelus Final Fantasy 13 chapter 9 is now 1.
I have not got to him yet in his third fight yet but im very close.
Second time i murdered him no problem.

10. Bowser (Super Mario World)
9. MechaGodzilla 2 (Godzilla Destroy All Monster Melee)
8. Gary (Fire Red)
7. Carnage (Maximum Carnage)
6. Gizmo (Gremlinstripe vs. Gizmo)
5. Red (Pokemon Silver)
4. Komato General Tor (iji)
3. Monster X (Cave Story)
2. Giygas (Earthbound)
1. Mecha Birdo (I wanna be the guy) (I DON'T HAVE FAST REFLEXES OKAY)

1. Skeleton Bowser (New Super Mario Bros)
2. Tabuu (Super Smash Bros Brawl)
3. Pkmn Trainer Blue (Pokemon R/B/Y/FR/LG)
4. General RAAM (Gears Of War)
5. Nitro (Crash XS)
6. Pkmn Trainer Red (Pokemon G/S/C/HG/SS)
7. FA Cup Final Team (FIFA 10)
8. Barcelona (PES 2010)
9. Ridley (Super Smash Bros Brawl)
10. Crazy/Master Hand (SSB Series)

This was a hard list for me to create and had to think through all the years of my gaming but here goes...

#10)Zeus (God of War III)
#9) Lu Bu (Dynasty Warriors)
#8) Lou the Devil (Guitar Hero III - on extreme)
#7) Machine Gun Willy (Double Dragon)
#6) Fontaine (Bioshock)
#5) Psycho Mantis (Metal Gear Solid)
#4) Dr. Wily (Mega Man 2)
#3) Dark Lord Ganondorf (Legend of Zelda: Twilight Princess)
#2) Mike Tyson (Mike Tyson's Punch Out)

and finally....

#1) Sepiroth (FFVII & Kingdom Hearts 1 & 2) - He was super hard in THREE games!!!


That last one for me just crushed me. I still don't think I've ever actually beaten him in FFVII and I still have my old playstation just in case one day I get the nerve to try and finally beat him/Chaos and the game.