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Play Alien Intervention from Amstrad Action in your browser

Alien Intervention is an Amstrad CPC game that was published as a listing in Amstrad Action (AA) April 1993. On this web page, you can play the game, and see the original listing as it appeared in the magazine. Click the game window to activate it (including sound), and then follow the on-screen instructions.

About the Alien Intervention type-in from AA

The idea of this game is to block the ladder parts that are dropped in from the top. If any one of the ladders is complete, the underground alien climbs out and zaps you. You can fire on the alien too.

The key to getting listings published in AA was not to make them too long, so lots of additional presentation elements were left out. (ACU ran much longer listings, including Wallbuster and Fishtank.) I've made a few modifications to this version of the game, including making the key combination more friendly, adding tunes, and adding the city in the background. Given how short the original game listing is, I'm pleased with how it looks and how fast it plays.

I like the way the instructions are revealed in this, one line of pixels at a time, which looks pretty smooth for a BASIC type-in. It was achieved by drawing the instructions in an invisible colour, and then XORing another colour on top, one line at a time. The text changed to a visible colour, one line at a time. Learn more about colour swapping in my BASIC tutorial here. Find out more about the XOR graphics mode here.

The sprites were designed using my Amstrad CPC Sprite Designer, which appeared on an AA covertape. The data for the machine code and the sprites was converted into DATA statements using my Data Maker tool.

Download my disc of Amstrad games and utilities to use in your favourite emulator here.

The Alien Intervention listing from AA

Scan of a magazine page showing the code listing for this program

Load another game into the emulator

Amstrad disc You can download my Amstrad CPC games and utilities disc to use these programs in your favourite emulator.

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