You nailed the light/dark interaction we were aiming for in our game. We also used the torches, but there was still too much light on the scene so they did not make that much sense.
Feedback on the snake character talking: Consider playing the audio clip once at the being; the loop is distracting.
Also, allowing the user to skip the story manually will give more control, I read faster.
Your dark effect is a good reference to improve our game