a skeleton for a simple basic scrolling game with r2d2

5 print"wait, moving ram":gosub 1220:rem moving charset on ram
10 poke 53281,0:poke53280,6:print"{clear}":rem colouring screen and clearing
20 gosub 1040:gosub1190:rem define rd2 sprite and fill buttom screen with chars
30 rem main cycle
40 gosub 1290:rem change char for scroll effect
50 gosub 1330:rem set char to its original state
60 gosub 600:rem joystick and moving routine
100 goto 30: rem eternal loop
600 rem joystick and moving routine
610 j=peek(56320)
620 if (j=123) then x=x-5:ifx<30 then x=30
630 if (j=119) then x=x+5:ifx>255 then x=255
640 poke53248,x
650 return
1040 rem r2d2 sprite
1045 x=150:y=225:rem r2d2 position
1050 sz = 832:fort=0to63:reada:pokesz+t,a:next
1060 poke53269,1:rem activate sprite 1
1070 poke2040,13:rem sprite pointer for sz=832=13*64
1080 poke53248,x:poke53249,y:rem sprite 1 x and y
1090 poke53276,1:rem multicolor sprite 1
1100 poke53287,1:poke53285,12:poke53286,6:return
1110 rem r2d2 sprite data
1120 data 7,192,0,31,220,0,63,80,0,61
1130 data 92,0,53,116,0,21,220,0,23,111
1140 data 0,29,171,0,6,171,0,14,219,192
1150 data 14,90,192,14,122,192,13,122,192,1
1160 data 154,176,5,166,176,7,234,176,28,234
1170 data 112,28,234,112,32,59,240,168,15,192
1180 data 168,10,160,0
1190 rem fill 2 last lines with petscii 208 purple
1200 for t=1904 to 2023:poke t,80:poket+54272,4:next
1210 return
1220 rem redefining charset
1230 poke 56334, peek(56334) and 254:rem (interrupts deactivate)
1240 poke 1, peek(1) and 251:rem (e/a area deactivate, char set rom online)
1250 for a=53248 to 57343: poke a-40960, peek(a): next a:rem (copy routine)
1260 poke 1, peek(1) or 4:rem (e/a area activate)
1270 poke 56334, peek(56334) or 1:rem (interrupts activate)
1280 poke 53272,peek(53272) and 240 or 12 : rem char set ram at $3000 (sets soft character base address)
1285 return
1290 rem modified char
1310 for t=0to5:poke 12930+t,24:next:rem character 80 redefined
1320 return
1330 rem original char
1340 for t=0to5:poke 12930+t,3:next:rem character 80 redefined
1350 return