There is a problem when attempting to run your game, but it is an easy fix. The executable file is called "FieldsAndFeldspar_Corner", while the _Data does not share the same name, instead being titled "WardensOfDawn_Corner". Both of these files need to share the same name. I renamed the .exe and it ran properly.
It took me a second to figure out how the upgrades worked, so I lost on the first level in my first attempt. I thought that they would be on a tower-by-tower basis and did not expect them to be overall upgrades. Once I figured this out, it became so fun. Stacking gold mines to maximize gold output and then just upgrading everything proved to be a great strat, as I would get up to 1000 gold per second.
I really like the main gameplay loop, but I wish there was a way to destroy towers that had been placed down, since I misclicked a few times in later levels. I also think there were a few instances in which costs didn't update. The gold mines stayed the same price to place throughout my playthrough, despite seeing they were supposed to go up in cost on the upgrade UI.