A breakout game in GFA basic for Atari ST

In the mid 80's, I had an Atari ST and I enjoyed writing very useless programs such as GFA-punches: short GFA programs (less than 20 lines) that had to be cool.

Among others, I wrote a 17 lines long breakout game.
Laurent Vogel, who is, as you can guess, an old friend of mine, had fortunately kept the source:

Hidem
Deffill 0
Input "entrez les coordonnees de la balle ainsi
que les composantes du vecteur vitesse initial :
",A%,B%,C%,D%
Q$=String$(14,String$(2,String$(80,0))+String$(12,
String$(20,Chr$(127)+Chr$(255)+Chr$(255)+Chr$(252)
)))+String$(16320,0)
C$=Mki$(8)+Mki$(8)+Mki$(1)+Mki$(2048)+Mki$(15872)+
Mki$(32512)+Mki$(32512)+Mki$(65408)+Mki$(32512)+
Mki$(32512)+Mki$(15872)+Mki$(2048)+Mki$(0)
Sput Q$
Repeat
  Put A%,B%,C$,7
  Bmove Xbios(2)+390*80,Xbios(2)+380*80,800
  Rbox Mousex,380,Mousex+79,389
  C%=(1+2*(A%<10 Or A%>629))*((Abs(Mousex+35-A%)>
20 And B%>364)*6*Sin((Mousex+35-A%)/28)-(Abs(
Mousex+35-A%)<21 Or B%<365)*C%)
  D%=(1+2*((B%<9 Or B%>364) Xor (Point(A%+1,B%+1)=
1 Or Point(A%+1,B%+8)=1 Or Point(A%+8,B%+1)=1 Or 
Point(A%+8,B%+8)=1)))*(-(Abs(Mousex+35-A%)>20 And 
B%>364)*6*Cos((Mousex+35-A%)/28)-(Abs(Mousex+35-A%
)<21 Or B%<365)*D%)
  Fill -1-(A%+5)*(Point(A%+1,B%+1)=1 Or Point(A%+
1,B%+8)=1 Or Point(A%+8,B%+1)=1 Or Point(A%+8,B%+
8)=1),-1-(B%+5)*(Point(A%+1,B%+1)=1 Or Point(A%+1,
B%+8)=1 Or Point(A%+8,B%+1)=1 Or Point(A%+8,B%+8)=
1)
  Put A%,B%,C$,4
  Add A%,C%
  Add B%,D%
Until (B%>364 And Abs(Mousex+35-A%)>50) Or Mousek

It looked like this (to be precise, what you see is the original program emulated by the Steem engine on my PC):