Here's my full game walkthrough with commentary:
Completion time is just under an hour, which breaks down to about 25 mins of gameplay and about 30 mins of unskippable cutscenes and loading screens.
edit: YouTube automatically edited some of the audio because of copyright. At the beginning of Chapter 2 (near 13:00 in the video), it begins to replay the introduction of the video. This is YouTube's automatic software doing this instead of muting the music. The normal audio kicks back in around 14:55.