Space Invaders One Button (C64)

This game is a C64 conversion of Space Invaders, the famous arcade game created by Tomohiro Nishikado in 1978.

This particular version is designed to be controlled exclusively via the joystick's fire button.

The game runs perfectly on both PAL and NTSC models of the Commodore 64.

If you are using an emulator on a 60 Hz monitor, it is recommended to select an NTSC model for smoother gameplay.

Gameplay

Space Invaders is a fixed shooter in which the player controls a laser cannon by moving it horizontally across the bottom of the screen and firing at descending aliens. The aim is to defeat five rows of eleven aliens that move horizontally back and forth across the screen as they advance toward the bottom of the screen. The player's laser cannon is partially protected by several stationary defense bunkers that are gradually destroyed from the top and bottom by blasts from either the aliens or the cannon.

The player defeats an alien and earns points by shooting it with the laser cannon. As more aliens are defeated, the aliens' movement and the game's music both speed up. Defeating all the aliens on-screen brings another wave that is more difficult, a loop which can continue endlessly.

A special "mystery ship" will occasionally move across the top of the screen and awards bonus points if destroyed.

The aliens attempt to destroy the player's cannon by shooting it as they approach the bottom of the screen. If they reach the bottom, the alien invasion is declared successful and the stage starts over with the loss of a cannon. When the player runs out of cannons, the game ends.

The player earns extra cannons based on the scores shown in the following table:

Difficulty level	First cannon at	Subsequent cannons every
Easier	1000	2000
Medium	1500	3000
Harder	1500	4000

A maximum of 9 cannons can be accumulated.

Options

There are 3 difficulty levels to choose from: Easier, Medium, Harder.

There are 3 color sets to choose from.

There are 9 fire sound effects to choose from.

Controls

While playing, the player's laser cannon will fire automatically and repeatedly. Press and release the joystick button to reverse the direction of the cannon. Hold down the button to stop the cannon's movement and stop shooting, so you can aim more accurately at the enemies.

To navigate the menus, short press the button to move to the next item and long press the button to accept the selection. Similarly you can enter the name for a top score. Here you can also select the character "RB" (rubber) to erase the previous character entry.

Joystick in port 2.

It is still possible to use the keyboard according to the following table:

F7	Pause
F1	Stop game and return to title screen
F1	Reset ranking (while the top scores are displayed)