This game is almost really good, but it has a few problems which make it worse than other free alternatives. It kept my wife and me entertained for 3 hours before we exhausted all of the lessons and activities.

1. In the match 3 activity, the cascading bejeweled effect in the blows out your speakers with simultaneous sound clips when multiple sets are aligned simultaneously. Sometimes the blinking visual effect also appears on cells which were not part of the combo.
2. In the slicer activity, identical characters can fall down where the first one does not match the target, but the second one does. I thought I was mistaken at first until two "a" characters were side by side and only the later one matched the "a" target.
3. The pronunciations do not help to distinguish similar sounds adequately. Duolingo struggles with this too, especially with "e" vs "ae" and "j" vs "jj" vs "ch"
4. An explanation for why some jamo appear differently in text boxes versus paragraphs would be helpful. Some consonants appear differently depending on the font being used, just like in English. I figured it out after some research but it would have been much better if the game showed how to write and recognize the jamo in all of their different writing or printing styles.