atari2600land is still working on his Qix style Atari 2600 conversion.

Release notes:

If I made the playfield 200 pfblocks, then I could just divide the # of pfblocks filled in by 2 to get a %. This is what I did in this next version. Also, the automatic line stops once you reach a playfield block, whether it be the border or not and adds the %age to the score (the 5th figure should be a ‘%’, I just haven’t gotten around to making it yet.

http://www.atariage.com/forums/index.php?showtopic=91578