Nice little puzzle game! I enjoyed it the full way through.
The controls felt smooth. I liked the use of lighting, too. Though I see the inspiration for flipping sides between light and dark, I would have liked to have seen the theme have a deeper influence on the game mechanics.
I'd second the criticism regarding the spike collision boxes being wider than I expected from the visual queue. I didn't have an issue with the blind jumps as much, as each time I took a leap of faith, I landed on something. The levels reloaded fast enough that 1 or 2 failed blind jumps would have been okay to me.
I thought the design of the puzzles and levels was good. They built up in difficulty at a nice pace, and none seemed too daunting to stop me from continuing forward. The game flowed from beginning to end.
Congrats on your first GWJ entry! Looking forward to what you make in the future.