Here is a quite lengthy video of HTC All New One (which has a codename M8) or someone might call it the All New HTC One. This video actually surfaced much earlier but it was taken down before I could see it. Now, someone has uploaded it again.
As you can see from the video, most of the features that were leaked earlier had been confirmed. However, the presenter did not really give a good overview of the device. For example, I am still not sure what the secondary rear camera does.