Waves are featured in Survival and Zombie mode. Waves also known as "rounds" count your current level. Every wave is slightly harder than the last. Also they are longer than the last causing the player to run out of ammo alot.
On zombies every wave adds 100 health to all zombies and more of them come. Some waves contian special zombies to add to the carnage. Special waves include; Hellhounds, Space Monkeys, and The Pentagon Thief.
In survival the waves add more people and they have better guns. Some waves are special and have special enemys. Waves Include; Bomb Squads, attack dogs, Juggernaughts, Choppers, Chemical Warfare, Claymore Experts, Riotshield Juggernaughts, Armored Juggernaughts, and regular Infentray.