My big problem with the episode is to build to quite a brilliant sci-fi idea that an entire planet is an alien, and then do absolutely nothing with it. For all the difference to the story it made it could have been a sentient pebble. Then the stuff with the leaf was nonsense. It would maybe makes sense if we, and Clara, were to know what she is and what her removal from the universe might mean but without that knowledge it was just another power of love resolution, and why is Clara so convinced it will work? When you think how the previous companion's "oooh look at how awesome time and space travel is" episodes where they first get to explore the TARDIS' full potential then it becomes all the more underwhelming. "End of the World", "Gridlock", "Planet of the Ood", "Beast Below" all much, much better ideas and shows. Hells, Saturday's episode felt like a cheap retread of "End of the World". And the less said about that bloody singing the better. For me the only thing of import was "I don't think it likes me"