This Spectrum game from Robert Hughes of Stoke Poges in Bucks takes you back to the '40s. You take the position of a pilot in the NAF (National Air Force). Unfortunately, due to your terrible luck and awful flying skills, you have been demoted to the lowest possible rank and given the task of manning the anti-aircraft guns.
Your only hope of achieving your lost rank and status is to shoot down as many enemy aircraft as possible. To help in this task you are put in charge of the new computer assisted sighting system (codenamed Blackcurrent).
Using your intimate knowledge of computers, you are able to tinker with the program by:
a. Increasing 10 in line 2010 to allow you more time, and
b. Decreasing (or increasing) the diff in lines 6 and 9003.
These hints should allow you to reach your goal (the officers' mess) in time for dinner.
Program Notes
3
Gosub and define the graphics characters
4
Gosub and print introduction and instructions
5-9
Set up variables and screen colours
10
Gosub to draw runway and airfield
100-125
Delete the sight using x and y as the horizontal and vertical positions
130-165
Scan the keyboard and update the sight co-ordinates accordingly
180-190
Delete the enemy aircraft
195-230
Redraw the sight using UDGs (User Defined Graphics)
240-241
Fire the Ack Ack guns and check for a hit
242
Check ammo. If there is none left then go to routine for end of game
245-247
Get a new random position for the enemy aircraft and check it.
248
Make aircraft movement sound.
250
Update the horizontal position of the aircraft by the difficulty.
260
Check whether the aircraft has flown past, if so the next plane.
300-305
Print the aircraft onto the screen.
310-315
Update the screen information such as score, number of waves, etc.
999
Continue the game
1000-1040
Enemy plane hit, explosion routine. In line 1000 the two graphics characters at the end of the line are code 137 and 134. The characters at the end of 1010 are 134 and 137.
1050
Select new start position for approaching enemy.
1060-1070
Update the score according to how close the hit was.
17th March 1984