So I've made it through the entire collection of new levels. Almost all of the levels have this issue with face-down cards and no way to play them. HOWEVER, there IS a way to play them. It involves the cards that pop up during play that have the imminent "volcano" eruption. Normally, one would want to play those cards before they "erupt" and add more cards to have to play. However, with these latest levels, you need to let them blow up. When they do that, they add extra cards, of course, BUT they do place cards on top of those stand-alone, face-down cards. Once the face-down cards have cards on them, they will turn face-up once you play the cards on top of them. It may take letting several cards blow up to get all those stand-alone face-down cards covered to allow them to be played, but it does allow you to eventually play all cards. This is a very sneaky thing for the developers to do...lol. But you CAN beat it! Good luck!!
(and I apologize if I'm being unclear above!!)