I wrote a little space invaders game in SVG (Scalable Vector Graphics) several years ago. It plays sound effects and has a few of the essential features within the game. I have recently modified it to work on Google Chrome browsers, since it was originally built to run within Adobe’s SVG Viewer plug-in which could only run on Windows 98 or XP platforms.

It’s a great game for people who are new to programming to get their feet wet and hack around with it. Some of the core concepts needed to modify the game to any great extent would be a rudumentary knowledge of JavaScript, SVG, and DOM level programming; you can run the game in the browser directly, there is no need to embed it within an HTML page although that is certainly possible, and you also download it here. You can move the player using the ‘A’ and ‘D’ keys, and fire with the ‘S’ key. The space bar pauses and unpauses the game.

Here is a little excerpt taken from the Space Invaders Atari 2600 manual:

Welcome to Space Invaders! Before you can begin playing, the first step is to place your cursor over the docking rectangle in the upper-left hand corner. Once the cursor has been positioned over the rectangle, click it and it should change color. Lift your hand from the mouse and you’re ready to play!

You are a recent enlistee in the Earth Defense Corps. For the past six weeks you’ve undergone grueling and intensive training. Now you stand at attention, nervously anticipating the most critical section of your training…

“Okay, kid, you’re on!” barks your commanding officer.

Quickly you climb into a laser tank. A second enlistee follows you. You each settle into deep, leather seats. With a soft whirring sound, the automatic hatch cover closes overhead. As your eyes adjust to the dim light of the laser capsule, you begin to make out the controls. Mentally, you check off each knob, dial, button, and display. For the next several hours you and the other enlistee with operate these controls to defend your planet in an attack simulation. The screen in front of you lights up. A column of bomb-dropping aliens advances toward you. What next? For a second your mind goes blank. Have you learned your lessons well? No time to refer to the manual now. Your commanding officers are watching and it’s your show.

Your tasks are to stop the invaders from landing on your territory; avoid enemy bombs; and score as many points as possible. The simulation ends when you lose all your lives or when any invader lands on your planet. If you destroy all 36 space invaders before they touch your planet, a new set of invaders will appear on the screen. Each new set of invaders will move a little faster than the previous set.

You begin each game with three shields. Initially, you are safe behind the shields. But as you and the enemy hit the shields with lasers and bombs, they become damaged and eventually disappear altogether. As the space invaders come close to the shields in their descent toward you, the shields will be destroyed and your only hope is to destroy the remaining invaders before it’s too late…

Categories: Games, Programming, Retro
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