M.A.D. (which stands for Missile Attack and Defense) is an arcade action game somewhat similar to Missile Command. You control a photon cannon at the bottom of the screen, and your goal is to protect six energy stations located to your left and right. Waves of rockets and other ships will fly by on the screen, and occasionally one will drop in an attempt to destroy one of the stations (as a warning on most levels, the enemy will turn white just before it drops). You need to make sure you shoot it before your energy station is destroyed!
Gameplay involves timing your shots carefully, as too early or too late and the enemy ship will hit one of your energy stations. The game gets progressively harder as the levels increase, with more ships appearing on screen at once. A two-player variation adds a new level of challenge, where you must work together to protect the stations.