How about adding a volume control for the sound effects? Sometimes I’d like to listen to music while working puzzles, and I’d prefer the puzzle sound to be at a very low volume. As it is now, it is usually louder than I like and clashes with my music.
This is a great idea and would be easy to implement, I think. It has been added as feature # 536. Check the status soon!
Hello slydog.
Now Eterna is supporting a volume control feature.
You can control your volume in the option menu.
So cool 
Nice, but it is still too loud even on the lowest setting when I am listening to, for instance, internet radio in another window and when the radio is turned up all the way. The DING DING DING is still rather distracting, though it is nice to be able to turn the sound off all the way.
Which means that the volume system needs to be refined, both metaphorically and literally.
Maybe the volume levels should be exponentially scaled?