It's a very easy shooting game.
They will attack in a platoon.
Let's shoot.

They are in the shape of rock-paper-scissors.
There are four types of bullets that can beat them (there may be others)

･Round bullet (white): Can beat any Janvaders
･Rock bullet (blue): Can beat the scissors Janvaders
･Scissors bullet (red): Can beat the paper Janvaders
･Paper bullet (yellow): Can beat the rock Janvaders

To move the player (tank), press the button and slide it left or right.
Release the button and a bullet will be fired.

Defeat all the Janvaders and clear the stage.
The number of bullets depends on the stage, but increases when you hit the Janvaders.
If you take 3 damage from Janvader, the game is over.
The game is over even if there are no more bullets left.