The critical issue would be the height of the strings and the accuracy of the fretting.   If strings are too high, not only is the instrument difficult to note, but the notes could also be a little off pitch when pressed to the fretboard.   This is a relatively simple thing to correct.   With the woodworking technology available today there is no reason why the frets should not be accurate.   That was most likely to occur when each slot was marked and sawed individually. I worked with some friends making dulcimers at one time and we experimented by placing fretboards on cardboard boxes, dulcimer cases, and table tops and got reasonably good sound each time.   So Wal-Mart is taking the obscure little dulcimer to the people. Enjoy!!!!