In terms of Call of Duty: Dark Ops, only one thing comes into my mind without any doubt that this "zombies" are the funniest area of the game, for me anyhow. You can play this video game online. It is a great source of entertainment. When I first started playing, I usually couldn't make it beyond level a few without dying. You can get black ops 3 zombies info from the web.
Playing with single player
Double player makes it tough for you to play the game. The screen is quite small, so you cannot view all the things with good detail, you can't buy a "revive" and two player revive is just not the same since there are not any zombies around whenever the second player revives you anyhow.
Work with your knife
This is the most common mistake that I made once i first started playing. Utilize knife for the first three levels or higher depending on your gaming ability. Here is a trick to know how many times you will have to stab the zombies to kill them; 1 stab per level.
Weapon choice is absolutely important for killing the zombies late in the game. You don't want to get your weapon too quickly; I'd initially wait for level 4 to start out using weapons for the issues mentioned above.