It's impossible to imagine the gaming world without Halo, as it's become one of the most successful and beloved franchises in history, having sold over 50 million units. When the original Halo came out in 2001 for the XBox, it was only four years removed from GoldenEye, the game that had revolutionized console first-person-shooters on the Nintendo 64. It speaks to the remarkable effort by Bungie that they could improve on what Rare did in such a short span of time, crafting a game that sparked Microsoft's first outing into the home console game. If it weren't for the success of Halo, it's difficult to imagine where the XBox might be these days. https://www.youtube.com/watch?v=i2X6JH4riIY While Doom had its "Doom Clones", Halo had what gamers affectionately refer to as "Halo Killers", which would borrow so many of the numerous things that make the game as great as it is. As the shooter continued to evolve past Halo, elements pioneered by Halo became commonplace in the industry today. Recharging shields, multiplayer and Master Chief replicas were all the norm after Halo. It's true what they say; often imitated, never duplicated.