Asteroid Field Battle

    While on a deep space patrol, you are suddenly 
attacked by the dreaded Electronians. They have 
thrown a large electro-barrier around a sector of 
space, trapping your ship inside. If your ship 
touches this field, your ship will explode. Their 
ships, however, can pass through the field unharmed, 
and they are coming to get you. You have a laser for 
defense, but it has the same range as the enemy's 
electro-bolts. In any direct combat, therefore, you 
will probably receive about as many hits as you 
score. Your ship does have a force field which can 
withstand 25 hits by the electro-bolts, but after 
that a single hit will destroy you.
    There is another strategy you can use. Bouncing 
around in the electro-barrier are four asteroids. 
Because of a design flaw in the enemy radar, they 
can only detect metal objects such as your ship and 
their own ships. They cannot see the asteroids. You 
may therefore be able to maneuver them into 
colliding with the asteroids as they chase you. 
Between your lasers and the asteroids, you must try 
to destroy as many enemy ships as you can.
Running the Program
    To run the program, type AFB and press ENTER 
(RETURN on some keyboards). The program will display 
a title page and ask if you want to load previous 
scores. If you have played the game before and saved 
the scores and want to compete against these scores, 
press Y. The score file (AFBSCORE) must be on the 
disk in the default drive.
    Next, the program will ask if you want to use a 
joystick. If you press Y, the program will then ask 
which joystick, A or B, to use. You make a choice by 
pressing 1 or 2 on your keyboard. The joystick 
should be in the centered position when you make 
this choice to allow the program to calibrate it.
    If you play the game with joysticks, you point 
your ship on the screen by moving the joystick up, 
down, right, left, or diagonally and holding it 
until the ship changes direction. Once the ship has 
changed direction, you may release the joystick to 
the centered position and the ship will maintain 
that direction. You fire the laser by pressing any 
of the joystick's buttons and holding it down until 
the laser fires.
    If you are not playing by joystick, you may 
control the ship with the keys in the number keypad. 
The ship will move in the direction on the screen 
that a number has in relation to the 5 key. For 
example, pressing 8 causes the ship to move up, 
while pressing 3 causes it to move diagonally down 
and to the right. If your computer has the cursor 
keys and the Home, End, Pg Up and Pg Dn keys on the 
number keypad, this will work whether the Num Lock 
key is on or off. If your computer does not, 
activate the Num Lock key before you start the game. 
You fire the laser by pressing the space bar. You do 
not need to hold down the number key or space bar 
once you have pressed it. If fact, it is better if 
you don't.
    After you choose whether you want to use a 
joystick, the computer will ask you what speed level 
to play at. You choose a number from 1 to 5, where 5 
is the fastest. The game will then begin. You will 
see the electro-barrier, your ship, and the 
asteroids. The enemy ships will soon start coming 
through the barrier. The computer will display your 
score and force field strength at the 
bottom of the screen.
    The game continues until your ship is destroyed 
by collision with the barrier, an asteroid, or an 
enemy ship, or by repeated electro-bolt blasts. The 
computer will display the scoreboard and your score. 
If your score is high enough to be put on the 
scoreboard, the computer will ask for your name. 
Type your name or initials and press ENTER. The 
computer will add your name and score to the 
scoreboard. If your name was the last name entered 
into the scoreboard, you can enter your name by just 
pressing ENTER.
    The computer will then ask if you want to play 
again. If you press Y, the game repeats, starting 
with asking what speed level you want. If you press 
N, the computer will ask if you want to save your 
scores. If you press Y, the program will save the 
information on the scoreboard in a file on the disk 
in the default drive. The program then ends.