Flailing On The Phon managed to both score near-perfect ratings and stay as the highest ranked game for eleven months. THAT is an achievement.
In part 46 of his Skyrim play through Sips shot fire at some fire at oil, and dared anyone to come for him. Then two drauge rose from their coffins and Sips shot a fireball at both of then, sending them flying back to their coffins.
Beating TWO Eyes of Cthulu at the same time with very little preperation in Terraria.
The Heisenberg in their new Tekkit series qualifies.