Human-Forerunner War

Possibly my favorite cutscene from Halo 4: the brief glimpse we get of the war between Forerunners and ancient Humans. Considering how advanced the Forerunner race was, to think that Humans were once the greatest threat they ever faced is incredible (and wickedly cool story-wise.)

Halo 4 was the first numbered title to include pre-rendered cutscenes, the only other Halo title to do so is Halo Wars (ODST's pre-rendered promo videos don't count), and I think it really makes the game stand out in the series. As it stands, Halo 5 is the only reason I'll be getting the next-gen Xbox.

I didn't use a spoiler thumbnail for this one because, well, it doesn't spoil anything. It's just a cool part that happens in the game.