You could watch a static video, but head motion would not be tracked in that configuration. They probably recorded with some sort of non standard fish-eye lens, so no video player will exist that could achieve the desired effect. A bunch of transformations have to be done to make the video work with cardboard (source, I have developed a quick demo with cardboard and OpenGL before).

There's multiple video players for Android that take 'oculus' style side-by-side video and allow you to watch it with head tracking. OK - the inter-eye distance and distortion<>lens mapping might not be 100% but it mostly works.