atari2600land has updated his single and two player simultaneous play variant of a very well known Russian block game.

Release notes:

I got in the mood to make the game even faster moving, so I don’t know how you feel about the flashing lines (if you get a full row) I had to delete them to make way for the new way the program calculates if there’s a line or not. This new way is IMO faster than the old way, and should make both the two-player and one-player games faster.

http://www.atariage.com/forums/topic/153710-2600tris/page__st__125