Would be nice if the money is collected by another means than having to click on everything. Also, too many "!" that take money when everything is already expensive.
With some improvements this would be a great game. All the defenses should not cost the same.
There should be build sites for towers. Enemies should start out weaker and there should be more waves of enemies.
For the money you make the rides and other attractions cost far too much.
Also, new rides, attractions, and stalls would be nice and more area to build.