This reminds me of the games Guild of Dungeoneering and a little bit of a late game of The Magic Circle
Check them out for some ideas if you are planning to expand the game.
I would really like to see different colors of ghosts and chests so they could be differentiated instantly.
Another thing that really begs to be changed is the start of the game - please start the player only after the first tile is set, the first-time player needs to get familiar with the UI and start at their own pace. I don't think that remembering three tiles is a threat to the game's balance.
Oh, and the camera pan is unpleasant. Please make it auto-snap at the end of the current level
I like that you have a credits screen, this shows that you spent time on polish.