This video from Did You Know Gaming? is a super interesting look at the history of Halo and the directions it could have gone other than the game so many know and love today. For example, several weapons that didn't make it into the game, like a machete, underwater spear gun and "gravity wrench." Also, instead of a FPS - did you know it could have been a real-time strategy game? This video gives us the inside scoop on everything from where the sounds come from to how the Master Chief got beefed up and how it ended up being a first-person shooter. Lots of other good stuff here - it's such an interesting window into game development and how such a hugely successful franchise comes to be.