Originally posted by: Brock Landers
Might and Magic III for SNES. You can trigger a glitch that locks the game and wipes your save.
Did I also mention it might be the longest game on the system? 20+ hours down the drain.
I've encountered a ton of game-ending glitches over the years, ranging from the random to the reproducible. One that comes to mind on the SNES is Porky Pig's Haunted Holiday -- it's very easy to accidentally clip through the scenery in that game, and sometimes it can softlock you. Another one is Harley's Humongous Adventure, which is famous for crashing with a "FATAL ERROR".
Other systems...I once had a winning run on Tower of Doom (Intellivision) spoiled when I mysteriously ended up outside the dungeon walls. Hard to know if that's failing hardware, a bug in the game engine, or what.
Also on the Intellivision, you can softlock Championship Tennis by checking your score at the wrong time. And I've had USCF Chess softlock on me repeatedly if the game follows certain sequences of moves. The Atari 2600 Video Chess game also has the reputation of softlocking/bugging out but it never happened to me.
A laserdisc FMV game I played, Kingdom II: Shadoan (Mac version), seems to have a bug that makes the game unwinnable on the lower difficulty setting (a key scene never becomes available).
Getting back to RPGs: Beggar Prince on the Genesis has a famous bug that can make the game unwinnable if you revisit a previous area, but I avoided it. However a later release from the same company, Star Odyssey, mysteriously corrupted my save game right before the final boss -- I had to replay the whole thing.