Earth Defense Force ROM

The Azyma Empire has established headquarters on the dark side of the Moon. After attacking the Earth, it is revealed they have a secret weapon being developed on the Moon, one capable of destroying all life on Earth. The E.D.F. is ordered to send their XA-1 fighters in to drive out the invaders and destroy their ultimate weapon. Released as a horizontal shooter game in the US in 1991, the object of Earth Defense Force is based on survival of the game’s levels, punctuated by the defeat of bosses at the end of each one.

It is a fixed-length game, with a proper ending at the completion of the last level. The player normally begins each level with three “shield” points, each able to absorb one enemy attack. The shield points are represented in the upper right corner by green squares under the heading “Shield”. Additional shield points can be earned once a predetermined game score is reached. Up to five shield points are represented on screen. However, a player can acquire more than five shield points, but they cannot be seen.

This is extremely rare though, due to the difficulty of the game and the score intervals at which additional shield points are acquired. Loss of all shields results in the loss of one of three credits, or continues, and loss of all continues results in the player seeing the game over screen. The game uses a unique leveling system, in which the player gains experience from defeated enemies to gain newer, more powerful versions of the weapons the player has access to.