Just went in and looked how the javascript on the page works (image urls are appended mathematically with the countdown date, so file name structure WILL NOT CHANGE), and dropping some links for you to keep checking back at:
Background Images:
http://www.square-en...in_bg_6days.jpg
http://www.square-en...in_bg_5days.jpg
http://www.square-en...in_bg_4days.jpg
http://www.square-en...in_bg_3days.jpg
http://www.square-en...in_bg_2days.jpg
http://www.square-en...in_bg_1days.jpg
http://www.square-en...in_bg_0days.jpg
Sound file links (should play in WMP):
http://www.square-en...QKL/sound_6days
http://www.square-en...QKL/sound_5days
http://www.square-en...QKL/sound_4days
http://www.square-en...QKL/sound_3days
http://www.square-en...QKL/sound_2days
http://www.square-en...QKL/sound_1days
http://www.square-en...QKL/sound_0days
BGM button images:
http://www.square-en...L/bgm_6days.gif
http://www.square-en...L/bgm_5days.gif
http://www.square-en...L/bgm_4days.gif
http://www.square-en...L/bgm_3days.gif
http://www.square-en...L/bgm_2days.gif
http://www.square-en...L/bgm_1days.gif
http://www.square-en...L/bgm_0days.gif
Background Images:
http://www.square-en...in_bg_6days.jpg
http://www.square-en...in_bg_5days.jpg
http://www.square-en...in_bg_4days.jpg
http://www.square-en...in_bg_3days.jpg
http://www.square-en...in_bg_2days.jpg
http://www.square-en...in_bg_1days.jpg
http://www.square-en...in_bg_0days.jpg
Sound file links (should play in WMP):
http://www.square-en...QKL/sound_6days
http://www.square-en...QKL/sound_5days
http://www.square-en...QKL/sound_4days
http://www.square-en...QKL/sound_3days
http://www.square-en...QKL/sound_2days
http://www.square-en...QKL/sound_1days
http://www.square-en...QKL/sound_0days
BGM button images:
http://www.square-en...L/bgm_6days.gif
http://www.square-en...L/bgm_5days.gif
http://www.square-en...L/bgm_4days.gif
http://www.square-en...L/bgm_3days.gif
http://www.square-en...L/bgm_2days.gif
http://www.square-en...L/bgm_1days.gif
http://www.square-en...L/bgm_0days.gif