hi WIZARD.
You can increase the number of times it plays, just change the last parameter 1 (playtimes) in the line:-
(*MusicChannelAsk)(RESOURCE_MUSIC, TUNESIZE, 1, 160, 1);//play tune in channel 1

0 is play once
1 is play 2 times
2 is play 3 times etc.
It's not a bug, I just decided that the tune might get annoying so just set it to play twice.
This version also has a pause game option.

btw here's Tetris2 with sound and mpx easter egg.
http://www.sendspace.com/file/nm0c3y