I know what you're saying and I agree, though technically you could program sprites and sound in C64 BASIC (well, if you consider PEEK and POKE "BASIC", heh...). In practice, you wouldn't have adequate performance. But still, the VIC-20 and PET versions were written entirely in BASIC! It's just the C64 version that wasn't.

Look at a VIC-20 screenshot, pretty impressive: https://www.mobygames.com/game/14475/sword-of-fargoal/screen...

Yes, I'm aware of the tricks done to make graphics out of the computer's character set. Still impressive in my book!