A classic 80's calculator game. Shoot down the invaders.

Digital Invaders originally appeared on the Casio MG-880 calculator.

This is a fast-paced action game that will put your fingers to the test.

INSTRUCTIONS

The aim is to score the most amount of points by destroying the invaders approaching from the right.

Use the AIM button to match the leftmost digit on the display with any of the approaching invaders. Press the FIRE button to destroy the invader.

If the sum of the shot down invaders is a multiple of 10, the next invader will be a UFO (shaped like an 'n') unless the stage is completed.

The defence lines next to the Aim Digit indicate the number of lives the player has left.

There are 2 levels and each level has 9 stages. In each stage you must shoot down all 16 invaders with 30 shots or less. The speed of the invaders increases with each successive stage. In level 2 the invaders start attacking from one position closer. After completing level 2 the game will return to level 1.

When the game is over, the display shows the stage that the player reached and the score.

SCORING

The high score is shown at the start of the game.

The points awarded for shooting down an invader depend on the invader's position. Starting from the rightmost position, the points are as follows:

Level 1
60, 50, 40, 30, 20, 10

Level 2
100, 80, 60, 40, 20

An extra 300 points is awarded for shooting down a UFO.

To share your scores online and see the leaderboard, sign in to Google Play Games.

SPEED

There are five speed levels. Level 1 is the slowest and level 5 is the fastest.

Speed level 5 closely matches the speed of the original calculator game. To be able to upload your score to the leaderboard you must be playing at speed level 5.

Speed measurements are shown below for the app and the calculator. Invader speed is measured by the time it takes for one invader to travel all the way across the display and cause one life to be lost.

DIGITAL INVADERS APP (SPEED LEVEL 5)
stage 1: 6.6 sec
stage 9: 2.2 sec
interval (score showing): 1.8 sec

DIGITAL INVADERS APP (SPEED LEVEL 1)
stage 1: 9 sec
stage 9: 4.6 sec
interval (score showing): 1.8 sec

CALCULATOR
stage 1: 7 sec
stage 9: 2.3 sec
interval (score showing): 2 sec