Deus Ex: Human Revolution. I got to this part in the game where I absolutely could not beat a boss. Consulted IGN and learned that the only way to defeat her was to have some ability that was only gained at some prior point. Unfortunately I didn't have any save points prior to that, so the only way I would be able to defeat that boss would be to completely restart. I just kind of noped the game after that.
This game is WIDELY criticized for this and has since been patched (via a new Director's Cut version of the game) to fix the oversight. Essentially, thr boss battles were outsourced to abother company, causing them to not line up with the implementation of the rest of the game.
You could make it through most of the game as a 100% stealth/hacking build, but a single boss towards the end REQUIRED some combat abilities in the vanilla version. They've since added environmental aids to keep you from this exact frustration.
Source: i too got EXTREMELY stuck here before they released the Director's Cut...