Sorry for the horrible video quality, had to shoot it on an old Nexus 7. Running on a Sony XBR930D, using APKs from a comment by /u/ShitConversationBot .
The end result as you will see in the video is that the sideloaded software is not yet ready for primetime on Android TV. The guide and software are snappy, but the Fire TV APK likely contains hefty video optimizations and reliance on specific accelerators in the Fire TV's firmware and potentially hardware that this Sony TV does not have.
Also, this is not a glitch. There is no audio coming from the stream when it loads.
The good news is that the Android Market version of DirecTV Now says that Android TV support is included (even though it isn't) so maybe they just pulled it for a few last minute touches.
Your video link just links to another thread. Awesome to hear some improvement though!