You're welcome to use the Mobile Site even though all the quizzes are not yet finished.
I recently finished a new Screencast Video, showing how the mobile site works, with a lot of additional information about it on our blog. Here it is:
We've completed lesson 23 and have begun lesson 24.
There are now 28* lessons up, with quizzes (over 80 hours of work for real beginners and pre-intermediate students). I have finally found the perfect format for both the quizzes and for the video formats for mobile devices (he said modestly).
Everything on the Mobile Site works well on my iPhone 4S. I have received feedback from owners of Android and Windows smartphones very recently. Our mobile site works very well on these platforms - perhaps better than on the iPhone!