Grid Race

Grid Race is a fast, all action game, in which you have to prevent "The
Runner" from reaching the bottom of a grid.

As well as this task, you have to also get rid of other creatures which work
their way down the grid at regular intervals.

On running the program, after the instructions, (which can be removed by
deleting line 70 and lines 6000-6160) you are faced with an eight by eight
grid with your base at the bottom. Use the keys as follows: 5-Left,
8-Right,0-Fire.

Variables Used

A$ = Graphic character, when defining graphics.
B$ = Title of screen.
c$ = Extra character on screen.
G$,H$ = Grid
M$ = Display of bases left.
B = Byte of UDG.
BASE = Column position of base on row 19.
C = Extra character on screen toggle.
EXX = Newposition of extra character.
EXY = Column position of extra character.
RUNNERX = Row position of runner.
RUNNERY = Column position of runner.
O = Old position of runner.
MRND = Holds random number.
CREAT = When CREAT = 0 then runner has reached the bottom.
        When CREAT = 1 then the extra character has reached the bottom.
FIN = Determines which random number to use.
SCORE = Holds current score.
HISCORE = Holds current hi score.
MEN = Number of bases left.
X,L = Used for various control loops.

Rundown

36   Reset scores to 0.
95   Test if extra character is on screen.
100  Store old column of runner.
110  Move runner on grid by column.
115  Move runner on grid by row.
125  Replace grid where runner was.
130  Print new position of runner.
135  Test if runner had reached the bottom.
140  Print base.
145  Test if to start new character on screen.
150  Move base.
155  See if fire button is pressed.
160  Fire.
165  Test if a hit.
300  330 = Choose extra characters.
335  Store row of extra characters.
340  Move extra characters by row.
345  Move extra characters by column.
350  Test if extra character has reached the bottom.
360  GOTO main program.
4000 Explode the runner or the creature and update scores accordingly.
4115-4195 Destroy the ship.
5000-5120 Define the graphics.
6000-6160 Instructions.
7000-7055 Set up screen.
7050-7085 Set up variables.
9000-9030 Display title.

-------------------------------------------------------------------

***Additional changes made to program as follows...

>Changed lines 86,87 to 36,37 and 88,89 to 61,62 to get the program working correctly

>Changed 6120 PAUSE 1e4 to 6120 IF INKEY$="" THEN GOTO 6120

>Changed the PAUSE 1e4 in line 4185 to PAUSE 0

>Removed the word 'score' from 'hi score' in line 7050 to stop screen overlap