Glitches and bugs can be fun when they do funny things or are exploitable. However, there exists a certain type of malfunction within a game's code that can absolutely destroy one's experience with it. This is referring to those glitches which, through one method or another, destroy or corrupt a save file.
Either they straight up annihilate the file or they create a state within the game that completely blocks progress. Thankfully, the advent of updates and cloud saves has made this less of an issue, though the scars of losing dozens of hours of progress will never go away for the victims of these happenings.
10 Grand Theft Auto: Vice City - Ice Cream Factory
The second half of Grand Theft Auto: Vice City sees the player buying up properties around the map and generating income. Each of these also acts as a save spot. When playing on the original PS2 release, never under any circumstances save at The Cherry Popper Ice Cream Company. Doing so corrupts the save file, forcing one to start the game over again if they do not have a backup. Fortunately, the second game of the PlayStation 2 Grand Theft Auto trilogy is a masterpiece worth experiencing many times over.
9 Batman: Arkham Asylum
Just like the Caped Crusader's ability to get the drop on unsuspecting criminals in Gotham City, so too does this bug surprise random players who just wanted to play what many consider the best superhero video game ever made. This bug has no logic and no known trigger; it simply deletes one's save file at any time, including near one hundred percent completion. Perhaps this is not a bug, and simply the Joker's cruelest trick.
8 SoulCalibur III - Save Corruption
The third entry in the legendary fighting game series features a bug that can wreak havoc on all the progress one made. Activating it is as simple as deleting files on the memory card.
Some also theorize that having games with changing file sizes also puts the bug at risk for occurring. Regardless of the cause, it almost seems like a good idea to have a memory card exclusively for SoulCalibur III at this point.
7 Elder Scrolls IV: Oblivion - Shivering Isles Glitch
Bethesda games are no strangers to wild glitches. They stop being cute when they prevent any further progress within the game, however. In the Shivering Isles expansion to Oblivion, there exists a slight chance for new items to stop spawning. This has to do with the expansion taking up too much space on the game's file, and the concessions made behind the scenes to keep it running. A patch eventually came out on the PC, but console players just have to cross their fingers when playing.
6 No Man's Sky
Those who preordered No Man's Sky were gifted a ship with a hyperdrive inside it, giving them the ability to use it before learning how to build one. If they take off to the stars before doing the right mission, the player can possibly end up stranded in space. The game came out four years ago, so no one playing it is taking advantage of preorder bonuses at this point, meaning the fear of running into this particular bug is pretty much nonexistent now.
5 Final Fantasy VI - Sketch Bug
Fortunately, this bug only occurs on the first runs of the original SNES version of the classic Final Fantasy title. Should Relm's sketch ability miss a target, this bug has a chance of taking effect. It can do things like randomly add items to the inventory or mess with the graphics a little bit, but it would not make it on the list if it also did not have the chance to completely erase the save file, a seriously dire outcome for a massive JRPG such as this.
4 Elder Scrolls Arena - Basically The Whole Game
Even when compared to other games from the developer, Elder Scrolls Arena was chock full of incredibly dangerous bugs that could ruin immeasurable amounts of progress. When playing the game, it is always a good idea to have several backup saves on hand. Today a game with so many bugs would be a death sentence for its reputation, but Elder Scrolls Arena was such a breathtakingly unique title, most people could look past it.
3 Paper Mario: The Origami King - Backtracking Glitch
Nintendo generally has a level of polish to the point where one would not expect to experience a horrendous game-breaking bug, but Paper Mario: the Origami King has one.
After receiving the VIP Card from the Toad in Shangri-Spa leaving and returning will cause the same Toad to act like Mario does not have the item, essentially blocking progress with no workaround. This is far into the game, too, so presenting no choice but to restart the file would cause many to simply give up on the journey.
2 Saint's Row 2 - The Freezer Glitch
This glitch stands out for its ability to ruin the whole Saint's Row 2 disc. Dubbed the Freezer Glitch, it only has a chance of happening if one goes out of bounds during the Zombie Uprising minigame. While exploring this area one was not meant to see, a mysterious shadow can show up, and at this point, it is already too late. Fortunately, popping out of bounds is not easy nor something one typically does by accident.
1 2004 PS2 Holiday Disc - Viewtiful Joe 2
This accursed disc contains a demo for Viewtiful Joe 2. Should one play it with a memory card inserted, the demo will eventually crash, corrupting every save file in the process. This demo came out around the time Grand Theft Auto: San Andreas and Metal Gear Solid 3 came out, so wiping away all the progress from these two titles without warning was particularly devastating.