The player controls a mobile cannon that moves horizontally in the background of the screen and must shoot down the aliens that slowly approach him one by one.
The aliens' approach stages follow a unique pattern, a broad and orderly progression that slowly but surely leads them to reach the bottom of the screen, decreeing the invasion and the consequent end of the game.
The cannon can be destroyed by enemy fire, by bombs that are periodically thrown by the aliens towards the cannon.
The user has an unlimited number of bullets but can only fire one shot at a time.
As aliens are destroyed, the remaining ones will increase their movement speed on the screen.
Having said that, I wish you a good game and good luck!