I think Beta has a way to go. I've been corrected for answers I think are correct, with and without the opportunity to say so. "Pay attention to the accents" is less informative than, say, the cedilla is used before the hard vowels. In general, more explanations would be useful - maybe because I learned my French and Spanish in classrooms. What you consider a correct subject, or lack of subject when the verb form makes it clear, is too variable for me to make up my own rules. It would help if you would provide more rules. I hope you'll find a way to include pr0onunciation practice with feedback. Thank you for your work so far.
I agree on this! But again, I'm VERY satisfied with duolingo and that it's free! This is one of the most important things in my opinion. Just don't let any adds spoil your work — I'd rather translate some extra sentences! In fact, I would be more than happy to do so (: