Yup, it's data driven. The data is stored in the csin array:
Global Dim csin(18)
(...)
Restore credit
For i =0 To 17
Read csin(i)
Next i
(...)
Datasection
credit: Data.l $34,$26,$1A,$10,$8,$4,$4,$6,$0C,$14,$1E,$2C,$36,$2E,$2A,$2A,$2C,$32
The stuff around
DisplaySprite(1,credx,400+csin(ccnt))
is responsible for displaying the logo on screen.