Starting life out as a mini-game, Nazi Zombies quickly became as popular as Call of Duty's main multiplayer mode (no easy feat), simply due to its addictive gameplay. The first map - Nacht Der Untoten - is as basic as the mode gets, but thanks to four player co-op and a leaderboard system, the thrill of reaching a new highest round never got old. It was through the maps added via downloadable content that the mode became seriously good; each adding a new gameplay feature that added to the challenge: Zombie Verruckt added perk machines; Shi No Numa added special zombie rounds (namely the Hellhounds); and Der Riese introduced teleporters and the Pack-A-Punch Machine, allowing players to upgrade their weapons to a more powerful (and more awesome) form. There were other thrills to be found in the form of the Mystery Box; spending points on it would spawn a random weapon, including ones not found on the map originally. This was also the only way to acquire the highly coveted Ray Gun, arguably the most powerful weapon in the game. The addiction may have worn off over time but Nazi Zombies is still one of the most entertaining zombie modes of all time; not bad for a post-credits mini-game.
I have an addiction to achievements, a craving for new bands and a dream to become Captain America. I once finished second in a Mario Kart 7 tournament so I'm kind of a big deal.