Great original concept. Well executed. Good grapics. I really enjoyed it.
I do however have a little critism:
1. The jumping doesn't always work. Sometimes my character didn't jump when I pressed the jump button. It wasn't easy for me to recreate when it didn't work, but I think it's something like this: Jump, land, walk a few steps, press the jump button again, and it didn't work.
2. I wound like the cursor to disapear when I'm not in "puzzle mode". I don't know if it's possible in Unity though
Otherwise I hope you introduce more mecanics as the game progresses. Mabye something where something in the background has an impact on the signs and the other way around. A little bit like in The Witness. I might be a little late on that suggestion though.
I can't wait to se the final product.