Unwinnable by Mistake/Video Games/ZX Spectrum Games

There are many ZX Spectrum games which can become impossible to complete due to bugs. Search the World of Spectrum forums for "impossible": there have been at least two threads devoted to such games.


 * A particularly Egregious example is Xavior, in which the end-game routine to unlock the final room doesn't work. This remained undiscovered for some 20 years because the game's designer went for quantity instead of quality, giving the game 4,096(!) rooms and thus making it infeasible to complete even on an emulator allowing one to periodically save one's position.
 * The Impossible Mission series:
 * Impossible Mission centered on assembling nine puzzles to prevent a Mad Scientist from blowing up the world. The catch? There was a bug in the programming of the Atari 7800's NTSC version, and of the Sinclair ZX-Spectrum version, that made the mission literally impossible: some of the puzzle pieces were hidden behind unsearchable objects, preventing you from obtaining them. This was specific to these two versions; the Atari 7800 PAL version and other formats had no (reported) problems.
 * Impossible Mission II had many ways to render the game Unwinnable, such as destroying a music safe by accidentally placing a mine instead of a time-bomb in front of it, rendering an area inaccessible with a mine hole, or running out of floor-moving or robot-disabling items in a tower, thus resulting in a music piece or passcode number being Lost Forever. Many players also saved the game with too little time left on the clock.
 * The original release of Jet Set Willy could never be completed due to bugs -- most notably, the "Attic Bug," which would permanently corrupt the game's data because a certain enemy in "The Attic" level travels past the ZX Spectrum's video memory and overwrites game data. As a result, some rooms would from there on kill the player instantly as soon as he entered. The developer/publisher originally claimed that the bugs were intentional (saying that the affected rooms were filled with poison gas) but later released some memory-writing hacks to correct them. According to The Other Wiki, about half of the releases of Jet Set Willy (it was released on multiple platforms) were Unwinnable By Mistake. The Commodore 64 bug made it impossible to reach all of the objects in The Wine Cellar, this may have also been corrected by people hacking the code.
 * Henry's Hoard, which was based on the Jet Set Willy engine (apparently without the knowledge of the original authors) had an unreachable victory sequence for a different reason. The last two rooms could only be reached when all 256 items had been collected. But some of the 256 items were in those last two rooms.
 * The Speccy port of Tiger Road was so bad that Your Sinclair took the manufacturers to court over selling goods of unmercantile quality. The judge ordered the software company to release a version with the bug fixed. This was only after Your Sinclair tried to use an infinite lives cheat to complete the game - and found out that, at one point, you either get hit by a bullet or fall down a hole. (Many players got around this by rewriting the code.)