I just installed Stone Cutter on my Windows 8 system, and I noticed that there was an error with the sound in Action mode. It basically sounds like there is some echo / delay effect on certain sound effects, particularly with the shatter effects, but possibly also with the lava impact effects. It makes the sound appear about twice as loud, too, so it's kind of bothersome to also hear ducking because of the loudness.
I have recorded a sample of how it sounds on my system, which can be listened to here. The first part is recorded from Puzzle mode, followed by a beep, and then a recording from Action mode.
My system is an Acer Aspire V5-573G notebook with the following specs:
Windows 8 (6.2, Build 9200)
Intel Core i7-4500U CPU @ 1.80GHz (4 CPUs), ~2.4GHz
Realtek High Definition Audio
I hope that you eventually may find some time to fix this !