After transiting the Maze From Hell, protagonist Duke Togo jumps left-to-right across some platforms and enters the boss' hideout, or whatever, at what must surely be near the end of the game. But returning from the hideout, the height of the platforms make them too distant a jump and Togo falls time and again into a pit. The pressure's on: there's a five minute countdown running and little time to waste, judging by the depth of the MFH. Surely I missed something, obviously there must be a way to do it, but that way did not present itself. I plan to try again one day to beat this game, in order to rid myself of the agony of that defeat.
Metal Gear (NES)
Usually when a game has me stumped I take a break from it and let my subconscious work on the problem while I do other things, but sometimes that approach backfires. After finding the glove that's used to tap on walls, I tapped on nearly every surface in the game in between a couple of weeks-long breaks, but couldn't find the right spot. Years later when I got internet access, I finally broke down and consulted a walkthrough to find out where the glove is used, and it was much to my shame that it was at a location that I'd found but later forgotten about during a break in play. I really let myself down on that one and swore to never use a tip again, but of course one should never say never.