Fun game, it's very creative, it's just a shame that I'm not good on games like this (I only passed the level 1, so I think my comment isn't pretty relevant lol)...
Answering the questions:
1. Placing tiles. The hero doesn't have any interaction that needs some player input. If the animation had more "feel", it would work as a great reward.
2. The placing tiles itself. I think that would be more clear if the icons turned around following the camera rotation, that would reduce the player error chances.
3. I would like to play it on Steam.