tcLines is written in pure Tcl/Tk and takes only 300 lines of code. It can work on any platform which has Tcl/Tk interpreter, as well as a tclet in Web-browser, if Tcl/Tk plugin is installed.

You can also get if from cvs:
cvs -d :pserver:anonymous@cvs.tclines.sf.net:/cvsroot/tclines login
cvs -d :pserver:anonymous@cvs.tclines.sf.net:/cvsroot/tclines co tclines
You can also change resources for standard widgets, used in tcLines.
Widget tree is:
c (Canvas)
fr (Frame) -> score (Label)
-> topscore (Label)
-> next (Canvas)
main (Menu) -> game (Menu) // Only in stand-alone mode
control (Frame) -> new (Button) // Only in tclet mode
-> back (Button)
See corresponding Tk widgets man pages for configurable options.