there are no artifacts in the recording because it was recorded on an Apple IIe which has slightly better video hardware. You do get some glithces on the earlier Apple II+

Later models you can bypass the floating bus/vapor lock and get VBLANK from a register (but IIe/IIc/IIgs all do it differently). I coincidentally released a 256 byte demoscene demo using this today: https://www.youtube.com/watch?v=iWq57yeu4gQ