Very traditional game but with a solid execution.
The balance seems well designed for the first two levels. It is often very close that enemies get through before you get your defense setup and situation stabilized. But the balance falls apart in the third level when you unlock the priest. The extra coins from priests clearly were not taken into account for the general economy, as you can easily fill the whole board before the final wave is even close to arriving.
Text is also awfully small on my screen. Legible but barely so.
Other than that, it is a solid entry. Easy to learn even without tutorials.