Interestingly, adding an extra person to the recording process didn't make it much more complicated. Last year I bought a Blue Snowball ICE which I've used a couple of times in my videos, which when placed on the desk in front of us picks up both voices easily without much of a drop in quality. It would have been harder to get audio to two different sets of headphones without some kind of splitter, but luckily I have a pair of Bang and Olufsen headphones with allow you to daisy-chain another set of headphones off them, so we were both able to listen to the audio from the game with minimal effort. Once again, I used the technique of running the HDMI audio from the console out of the back of the monitor and into the Line In of my PC, so we could just listen to the audio output from the computer itself.
Not everything was plain-sailing, though. Before we began recording the Roxio started misbehaving, causing Windows 10 to crash twice before I moved it to a different USB port and it seemed to calm down. That wasn't the last of the trouble though. When I hit the 'Stop Recording' button in the Roxio software I had a sudden thought about what happened to my last episode of Shadow of the Colossus, and quickly made a copy of the raw MT2S file before it was automatically deleted in the encoding step. This proved to be a smart move because whilst the encoding completed successfully some time later, about 6 minutes into the MP4 the audio disappeared!
Since I had made a backup I was able to create a new MP4, but this was a huge shock and I have resolved to never again use the MP4 recording option in the Roxio software; it's just too unreliable and when it fails, there's nothing I can do to recover the recording. Transcoding the raw file manually adds an extra step in the process, but being able to keep a backup in case of transcoding failure is vital.
I have no idea what caused it to fail this time. Originally I thought that making my own copy of the raw file was the cause; perhaps my copying the file interrupted the file stream in the encoder and caused some kind of unresolvable desync between the video and the audio. However after re-encoding the final MP4 still had a minor corruption at exactly the same point that the original MP4 lost audio, which you can see in the final video above. This suggests to me that there was a weird blip in the recording that the manual transcoding was mercifully able to handle.
I'm looking forward to diving further into the game, and continuing to develop the on-air rapport between Lux and myself. There were some really great moments between us (when we both say 'Whee!' when sliding down the chain being a highlight) and I know we'll have more in the future!