The real problem about music was not the 15 seconds track alone, the problem was that every dialogue it resets and that's pretty hurtful for ears like mine, i'm pretty annoying on this kind of stuff (neighborhood knows something)
And the problem with the fourth level was the colors mostly, because i could follow lines but the background was pink and the pieces were pink too so sometimes i didn't even find the cut piece and had to click blindly. Maybe was my monitor that didn't have much contrast? I don't know but that was my issue!