Another interesting Bios routine is the "Game Select" routine. It handle the complete input and print for you. One of the parameter is at $BFED, is the number of levels.
You call the routine with jsr $FE83 in your loop. You can also define the places where the informations will displayed. I checked 5 games and all use this routine.
Of course you can not use it in Mode2, but for most normal projects is useful.
The Bios Game Select Routine
Re: The Bios Game Select Routine
Cool set of routines, it seems the BIOS contains more useful code than I had anticipated.