Call of Duty: Black Ops 3 has now released and offers hours upon hours of gameplay through just the usual three game modes found in Treyarch games, campaign, multiplayer, and zombies. However, there has been one other game mode thrown into the mix here that really adds a lot to the experience that you have to unlock.
That new mode in Call of Duty: Black Ops 3 is known as Nightmares mode, which actually takes the existing campaign mode and throws zombies into the mix. This may be something that some gamers want to try before anything else, but you will have to play for a little bit to get it.
To unlock Nightmares mode in Call of Duty: Black Ops 3, you will need to start the regular campaign and completely finish it. It appears that this is the case for every difficulty level, with Nightmares being available as soon as you complete it.
This is somewhat similar to how the zombies mode would start up after the conclusion in the first Black Ops, and this will be available from the main menu from now on.
Nightmares mode is a very neat option to add into the game and definitely worth playing, so definitely play through the regular campaign first to unlock it.