15 Most Brutally Hard Video Game Moments Of The Decade (So Far)

9. Fighting Sans On The Genocide Run - Undertale

Don't be put off by its primitive, ancient exterior - Undertale is as alert and ready as any sprightly, new-age release. It's always watching, always taking note of your various choices, leading to a number of different "runs" you can take across the game, alongside optional boss fights.

One is Sans, the pun-happy skeleton who most of us befriended, thanks to his charming ways. Yet, if along your journey you kill all in your way, not only will that pee Sans off as, well, you're offing his hometown and all his friends, but you'll end up killing Papyrus... his brother.

This leads to possibly the hardest boss fight in the game - one that sees you piloting your tiny heart icon against a literal barrage of claustrophobic screen clutter, all coming in at a stupidly fast clip.

Sans puts up one hell of a fight, almost like developer Toby Fox was saying, "Okay... if you really want to kill EVERYONE, it won't be as easy as you think..."

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