What happens when you mix Defender, Scramble and Chopper Rescue together, and put them out as one game? About the same thing as mixing ice cream, spaghetti and steak. By themselves they're each terrific, but when mixed together they make something that you don't even want to think about. This is what happened in Fort Apocalypse.
This game has the "rescue the hostages" theme from Choplifter!, and also its bombing mode. It has the caves of Scramble and the movement and firing of Defender. Fort Apocalypse has to win some kind of award for consistently mixing oil and water.
The game begins on the Defender-like upper level, where you encounter some weary-looking aliens who practically refuse to move. You fire this terrific burst from your twin guns and the beams are absorbed by the alien, without any damage to it at all. Apparently your firepower is a joke - you have to hit everything just right in order to destroy it, and sometimes (to add excitement to the game?) the enemy simply refuses to be killed.
Well, after that you descend into Scramble-like cavern passages, where you are supposed to find and rescue the hostages. Down there you are opposed by a number of adversaries - enemy choppers and missile launchers - which are also present on the top level.
The graphics aren't bad, but they've been done by someone with no sense of interior design. The walls are a nauseating pinkish-purplish color. That problem is solved on the second level where the walls are invisible. It takes somebody with a deeply masochistic bent to enjoy playing a game where you blow up after running into something that you can't even see.