Yea, sorry, I didn't mean that the music was bad. Just that it get repetitive when it's the same one for each level. Alternating between 2 would have done the job.
For the timer, I tough it was random between 2 variables that changed for each level. Like random between 7 to 10sec. It was probably because it changed for each color like Abhishek said. I just tough it was a bit long sometimes when I missed the puzzle and had to wait for 2 cycles to redo a part.