Widget layout, clock and date formats
Gradient and alpha blended colors
Blur and Shadows
If you have ideas, designs, suggestions or found bugs feel free to visit the forum, email or reddit (user knoxcoder).
Buy mClock.donate to support development
Also check out Chronotopia beta (http://forum.xda-developers.com/showthread.php?t=1001203) which is the replacement for mClock