This app is truly innovative. It does the same thing as my Stress Eraser -- a medical device costing $200 -- for a fraction of the cost. It works when you get the hang of it, but could really use more biofeedback, beyond the waveform. Some features Id like to see: * Sound feedback so you can close your eyes * Relaxing soundscapes and/or guided meditations * Spoken or written in-session encouragement and suggestions based on your performance, e.g. "Try slowing down your exhale" * More explanation on how to read the waveform Id be happy to pay extra for these features. Im giving it four stars for now with the hope that an update or pro version will come soon.