Various new words not shown as new or even shown at all; Issues with teaching style
First and foremost: I've noticed quite a few times that words in a section are either A.) Not shown in bright orange as a new word or B.) Not shown in the course. An example of B is: I went through a section, then when I went back to strengthen it, there was the word "friend," which hadn't been taught beforehand.
Now, for the part I see as MOST important: The way the course is taught. The course does not teach how letters are made, what letters make what sounds (for example, letters with double lines producing "y" sounds before the vowel or ㅅ being "s"), various VERY important grammar rules (Like is [있] vs. isn't [없]), how to format letter blocks, and more. I know Duolingo has a set way to teach languages, but it is incredibly inconvenient for vastly different languages such as Korean.
That's pretty much all I have to say. The second paragraph is my opinion on the teaching, but it should definitely be considered. Thanks for reading!
(If anything here was wrong, it's because I'm learning from Duolingo and Google, and anything wrong is not explained within the course.)
I don't understand what you mean about not teaching you anything? Everything that you've described is in the Tips and Notes sections.
As for the not highlighting new words (or even showing them on hover-over, as I've discovered), I can see how that would be frustrating. Since the new lesson format (from the heart-system to the repetition of wrongly answered questions), I prefer to get things I don't know wrong, as it will ask me in a few minutes, thereby strengthening my knowledge of the word. But perhaps that has more to do with my own style of learning.
The Korean course at the moment does indeed seem to throw us a little in the deep end. Since we're using a completely different alphabet things are already quite difficult, and even then the difficulty seems to ramp up quickly. However I'll still stick with it - it's still a beta release after all! And we should certainly acknowledge the long and difficult task that the Duolingo Korean team had putting together this course!
I completely agree with you! As much as I love duolingo, I can't stand the Korean course (for mobile at least, haven't tried it on pc). The teaching is awful imo, it makes it really hard to actually complete lessons. I wouldn't suggest it to any beginner. If you don't mind me giving you a recommendation, I'd suggest using the app "lingodeer", I've found the Korean course on there to be fantastic so far.