I enjoyed the game a lot. I think the art style is really awesome and cohesive, with the simple shaders and animation breathing a lot of life into the environment and unifying the light theme and feel. The light scenes are extremely picturesque as well. The music is ambient and fits the game tonally. The eye for environment makes the game feel complete and is so impressive for a jam game.
It did take a minute to even understand the logic of the game, even with the instruction booklet... but other than that blip, it was well telegraphed, and played flawlessly. I was skeptical about the logic of the game and how far you could take the light mechanics, but I found myself puzzling along seeing the increasing challenge (and realizing that yeah you can probably take this pretty far if you wanted, especially by restricting items). I thought shadows were a really inventive take on these light puzzles.
Unfortunately, I did not see a win condition due to a black screen bug in normal mode after about 12?15? levels.
Any criticisms I have about the game are minor and mostly out of scope for the jam. A few quick things in-scope would be: Level indicators in normal mode would be nice and a level reset/step-back button would also be nice.
Otherwise, outside of the jam, my number one add would be an in-game tutorial.
Other opinions I have: I didn't necessarily feel like scrolling between light sources added too much to the challenge. I feel like it would have been fine for each level to have one light-theme. I am a little conflicted on the items menu UI collapsing; it tends to add more clicks than necessary, especially flipping between items and item settings but I wasn't annoyed by it so it was noticeable to me but also probably fine.
Finally, I think that levels can get really, really busy with the million light rays which become more of a challenge to deal with than the actual puzzles, but I have no clue how you'd rectify this and it's probably totally fine and a skill issue for me.
Very prolific dev work, congrats to you both for the release!