Asteroid Field by Pitfall Jerry

1CLS0:PX=RND(62):SC=0:?"AVOID THE ASTERIODS BY":?"USING a AND d TO MOVE"
2FORD=1TO2000:NEXTD:GOTO7
3S=PY+150:K=PEEK(17023)ANDPEEK(2):IF PY<=0 THEN 7
4PX=PX-(K=ASC("D"))+(K=ASC("A")):IF POINT(PX,PY)<>0 THEN 8
5SET(PX,PY,7):PY=PY-1:SC=SC+1:SOUND S,1:GOTO3
7CLS0:PY=31:FORM=1TO100:X=RND(63):Y=RND(30):SET(X,Y,4):NEXTM:GOTO3
8CLS:?"YOU HAVE HIT AN ASTEROID!":PRINT "YOUR SCORE IS";SC
9?"PLAY AGAIN";:INPUT A$
10IFA$="Y"THEN1:END