Update 3I spent some time learning about Unity's new UI framework, its scaling, and how to make it fit properly in varying resolutions. Supporting all different sizes is a bit of a pain, but definitely easier than it was in the pre-Unity days!
As for the game, I've added some helper icons when you pick up a hexagon to indicate where a valid move is and isn't. I image that these won't be necessary as the player progresses, but they're a good tutorial-type feature as you're learning which tiles can replace which tiles.
Also, I added random weather effects which will occur and scramble the board a bit (active and inactive weather events are indicated in the upper right). Hopefully this bit of randomization can cause some hectic fun when trying to maintain board balance. I'm still tweaking how often these should occur, how random they should be, and how long they should last.
Genesis - Causes Trees to rapidly grow from random amount of Earth tiles.
Wind Gusts - Causes Fires to rapidly spread to random amount of Tree tiles.
Landslides - Causes Earth to rapidly slide in to random amount of Water tiles.
Heavy Storms - Causes Water to rapidly extinguish random amount of Fire tiles.