Really fun puzzler! I haven't understood the height system until quite late, and I wish there was a way to tell exactly how high a tile is, since the game mentions some tiles like height 5 or whatever, but I can't know for sure at what height any one is.
I'd also have liked to be able to see upcoming tiles, so I can plan my next move better, and to have the tiles that allow you to expand the isle as separate chunks, as in lets say every 10-20 points you get 3 tiles which are purely expansion, instead of having them mixed with other normal tiles.
It would also be nice to rotate the camera so I can get a nice picture of my city, along with maybe weather effects :). Also, an in game wiki or something to show me all possible tile types would be nice, as well as letting me be able to learn them at my own pace.
Some limits for the camera and animations for tiles as well as the sea would also look amazing!
And lastly, I think this game could be further developed to be level based, like each one asking you to reach a certain amount of score, with different starting island sizes and different pools of tiles that you can get. There's lots of possibilities with this game, and I hope you will expand it further post-jam as it clearly holds a lot of potential!