I'm glad you liked it!
I agree with you about the resources, it might need rebalancing. As for the mines, it was intended that you destroy your mine once it gets in the way or falls underwater and rebuild it somewhere higher, but now I find it a bit weird.
I feel that the whole building system needs a rework, because right now waves are too punishing for the new players, who don't know what to expect from the waves, while building up to the top right corner makes the game too easy.
Thanks for such great feedback!