That's odd... I don't have any of that sluggishness here o_O

Rest are good points.

Comments from a fellow Tetris programmer

The first thing I noticed was that this widget is huge! It could be compacted into a much smaller area and use a lot less screen real estate. Remember "tight makes right"

Next I noticed that the widget was not immediately responsive. If you hit a key, say left or right, the widget waits until the next "move" update to perform the action. This makes the widget feel "sluggish" and at worst "broken" somehow. Except for pushing the "down" key, all other movements should be performed independently of the default/regular downward motion.

Third, this is supposed to be a fun game and all I see is black, white and red all over; let's see some colour and some backgrounds!

This is a great base for further development, but I honestly don't think it is quite ready for release.