Not sure if it's a glitch, but the pause trick in Blaster Master for NES. On certain bosses, if you throw a grenade and pause while the explosion is animated, the explosion continues to damage the boss. After a bit, you can unpause and if the damage accrued is greater than the life of the boss, they insta-die.
While this glitch is well known now, i discovered it accidentally when i was just a lad.
The animal-people from Red Dead Redemption. Sometimes people will spawn where animals are meant to be, so you have the model of a person acting like a cougar or a bird. My favourite being the fully ridable donkey woman.
While I like Missingno, I'm still nostalgic for world -1. Why? Because reasons.
Interesting that they would mention FF6's Vanish/Doom, which technically isn't a glitch but an abuse of game mechanics combined with programmer's oversight, but leave out probably my favourite of all time, the Sketch bug, which is most definitely a glitch.
Stumbled on this one the very first time I played through the game and found myself with, among other things, a virtually unlimited supply of Gem Boxes and Economizers. Now that was a fun broken game.
In Resident Evil III, well into the game, Jill comes around a corner and there is a momentary flutter high above her head. Like the tinkle of breaking glass at the beginning, this suggests that an unexpected attack will soon come. For a long time after, I kept an eye on the sky, waiting for doom, but nothing ever appeared.
Missingno definitely qualifies as my favorite ever, that's no question.
However, barring that, there's also a really useful glitch in Fallout: New Vegas I like. It's really more of a combination of two different glitches, but the results are AMAZING.
By performing the early quests in Goodsprings in a VERY specific manner, you can cause a dialogue challenge to become infinitely repeating. So, this nets you infinite experience. But that's not all. The challenge ALSO rewards you with 9mm ammo, and leather armor. So this gives you infinite items to trade for caps.
After ALL of this, leave Goodsprings. This will cause the game to ask you if you'd like to re-make your character. Say yes, then make your character however you want. This causes the game to reset your level back to level 1. After you're done, the game will re-reward you with all the experience points you earned, raising your level back up to whatever you left it at. What's the point of this? Simple... double perks. Yup, while the game will take away your experience points and levels, it WON'T remove any perks you earned through the glitch. So, resetting your level and leveling again in this manner will let you earn TWICE the normal amount of obtainable perks.
With enough patience, you can more-or-less begin the game as a max-leveled, double-perked, infinite-caps loaded badass.
Anyone remember the Champions of Norrath games for the PS2? (I'm pretty sure those games existed for the sole purpose of allowing players to create and level new characters for that Everquest game, but they did have their own standalone campaigns as well.)
I can't remember exactly how it went, but in the first CoN game, there was a glitch in the character creation menu that could give you near-infinite skill points. What you did was, basically, select a race (elf, barbarian etc) OTHER than the one you wanted, allot the skill points in a certain manner - then deselect that character, choose a new one - and you'd get to keep the skill points from the previous one as well!
AND the process was repeatable.
You had to keep from getting too greedy, though - the game wouldn't let you move past character creation until all skill points were allotted, and each skill only went to 99, so it was entirely possible to aquire too many points - and be stuck!
A couple of more modern examples (both from Saints Row 2:)
If you go cruising through the sewer tunnels below Stilwater, vehicles intended to spawn on the parking lots above will sometimes appear down in the tunnels with you. This almost never happens, which is what makes it so cool - you don't see it often enough that you ever really come to expect it. Each incident is a surprise. The really strange thing is, though, that whenever it DOES happen, the vehicle will almost always be a motor home!
Also, I don't know if this really counts since I've only had it happen once, but you know that early mission where you have to recruit Shaundi? And impress her by hitting a few jumps with her car? Well, one time when I missed that jump over the canal, the car sort of clipped into the wall, my character went flying through the windshield - and promptly died. Somehow, she was also catapulted miles away. Next thing I know, I'm looking at a "wasted" - screen which shows her as a Team Rocket-style speck in the sky! I've no idea what the hell happened, but it was SO worth the hospital fee!
On that note, I'm definitely going to boot up GTA IV tomorrow and look for a swingset! Thanks for the tip, guys!
Becoming Fierce Deity Link outside of boss rooms in Majora's Mask. Even if it could easily end in the game being frozen or weird glitches occurring, having an eight foot tall over-powered Link running around Termina is so awesome.
I'll give missingno a little mention, I remember how cool it was to get 99 master balls and rare candies anytime I wanted, good times.
Don't know if this is a glitch, oversight, or debug option, but in Megaman 3, if you plug in the second controller and press left or up (forgot which) and then jump, you would have a super jump. This trick would also save you from dying in bottomless pits (though not spike ones.) Fall in a pit? Well press the direction and jump real quick no harm is done. Except the music stopped.
Also in MM3, if you press the other direction on the second controller (up or left, again I forgot which was which), you could slow the game down. Hold down A on the second controller along with the slow-mo and you would get extreme slow-mo.
How would a person accomplish this, I hear you asking? Feet. I played Megaman 3 with my hands and feet. Father used to tease me about it a lot. So to get him back, I'd beat him in Super Mario Bros 1 while playing 1 handed.
i laughed so hard at the commentary for the GTAIV swing set cannon glitch and i can just about imagine someone doing that anyway i dont tend to get glitches for some reason and the ones i do get are just annoying and not funny i would prefer to have funny glitches
Easily the best glitch, since it took a game and broke it over its knee with a sickening crack:
Necro/Retissue glitch in Tactics Ogre: Let Us Cling Together for SNES (Japan) PSX (US)
Necro was a high level dark magic spell only castable by a couple classes found at the end of Chapter 2 (well before you can use it) which revived a teammate who has died in battle as a skeleton or a ghost. Useful, because skeletons and ghosts keep stats, and when killed they revive in 3 turns unless hit by holy magic, which most enemies don't have.
Retissue was a dragon magic found near the bottom of the last huge dungeon. It made any skeleton or ghost hit by it turn back into a human... at Level 1... with 50% of their previous stats.
Doing this on the same character three times gave a character that took 40 turns before any other character could move, hit for max damage every hit, dodged every possible attack, and broke the game entirely.
Kinda lame, only ProJared delivered.
Best glitch I know of - i don't know of many - is the weapon swap glitch in Gunz, which was left in the game because it was the only thing that made it interesting. Only glitch that carried a game.
Second is tomb raider's boobs. While not a game glitch, during a remodeling of Lara, her tits were unexpectedly enlarged. Wheteher it was an accident or not is arguable.
Bonus round: Apparently the speeding up in space invaders was a glitch. that's my new best glitch ever.
In Deadrising 2 during the Helicopter boss fight you can destroy it in seconds with the toy spitball gun. Funny thing is I didn't discover this by accident I actually worked out that it would probably happen due to how you're supposed to fight the boss, tried it, and nearly pissed my pants laughing when it did. I should mention that this was when the game first came out so I was one of the first people to discover this which is also part of the reason I love this glitch so much.
I have three. Can't choose between them.
My first was from Fallout 3...I dont even know how this happened...I was in an intense firefight, then whipped out the Fat Man MIRV and fired.
I was breifly aware of there being an almighty explosion in front of my character before he flew into the skybox in 6 different directions. Either my Fat Man had malfunctioned and exploded as i fired, or someone was an INCREDIBLY good shot and shot one of my mini nukes just as I fired.
Second, I managed to basically cartridge-tilt a Wii game. See, there was this glitch in Twilight Princess, where if you went up to a magnetic zone, if you unequipped your Iron Boots mid-"flight", when you landed you would run at normal speed. Any speedrunner will swear by this. But...for me, something went wrong. Link started seizuring out as he walked. I tried to get a camera, but the game crashed before I could get it.
And lastly... http://www.youtube.com/watch?v=_LZEChcRAYE&feature=related
I remember going back to play Super Metroid on my Wii because I'd finally found clear instructions on how to access certain "glitch rooms", which is basically what happens when the game's code tries to fill in a screen tile that isn't allocated. As a kid, I spent days and days hugging the walls of Norfair in the hopes of triggering *something* - pretty much anything.
As for fictitious glitches, I'd definitely have to mention the BEN DROWNED creepypasta. The idea that a save file could be so corrupted as to be impossible to erase and that it could actually play themes backwards or perversely put art assets to use? That's - awesome. Plainly and simply awesome. It's also terrifying.
As a pioneer of burglary and house theft (thats right house theft, taking someones house) in UO year 1-2 I could sit here and wax lyrical all day about how joyus some of the glitches of UO were back then. But perhaps a couple of the favorites were... Going stealing with a buddy, one kills the the other, or get yourself killed by a bear or something, then stand just inside the door of someones house and have your friend stand on the step and cast resurrection (which had a one tile area affect back then) and bingo you are ressed in someones house, open the door, grab the pack horses and commence looting!
Alternatively, you could mark a rune on the ground next to someones house, then place 2 boxes on and next to that spot, then open a gate to the spot and the gate would open on the tile above the box, step out on to the other box, put another box on top, keep going with that method till you are at roof level, then step off into the house, because the roof wasnt solid lol. Open the door, grab the horses.... etc :D
I got a million of em....
Oh and if I ever looted your house... Im not sorry btw :p
I don't quite know if this is properly a glitch, but it helped me survive. If, in the game MACBOSS (a roguelike set in a futuristic world), you make a seductive female con artist with the highest Charisma, then go to the Charisma-boosting shop in town, you get money. And you can do this over and over, allowing you to start with the best gear in every town, which greatly increases your chances of living.
In Lego racers, after gathering enough bricks for a time travel the screen would very occasionally go a bit glitchy, and I would lap my opponents rather than just going further down the track a bit. That was so cool.