This is a good remake of an old Atari game. You defend the underwater city of Atlantis for as long as you can.

You control two AA guns mounted on either side of the city as well as a flying saucer. The left mouse button controls the left gun, and the right button, the right gun. If you press space bar your saucer will be launched and you can fly it around, shooting at enemies.

There are various types of enemies that will attack the city. The longer you hold them off, the more will come at you.

The enemies come from either the right or left side of the screen. Each time they pass over the city, they will return a little bit lower. Eventually lower enough to destroy parts of the city.

Atlantis is a very simple idea for a game, but it can get very tough to hold off the hordes of enemies.