Actually, never mind about that. While lying in bed not being able to sleep I randomly realized what was wrong. 😵 I recently disabled hardware acceleration in my browser to fix some other issue. When it's turned on everything works as expected.
Played through it again at the intended speed and I can only say it's a really nicely crafted experience. I hadn't picked up on the computer hanging being intended in my first playthrough. It's a clever touch that really sells that moment. Nicely done. 👏