This game has potential. I am kinda disappointed like some of fans are with this game doesn't mean its bad. I definitely still have hopes this game will improve. Developers if you are reading this please take in the following suggestions for future updates:
1. Port Heroes and Towers from Vengeance (hell even older titles) to this it would make the experience much more fun and experimental with tower and hero combos. You could make them a dlc pack and I would buy it.
2. Make another endless level like with kingdom rush origins, frontiers and the original kingdom rush (maybe even make one for vengeance).
3. If you decide to take in number 1 into consideration then skip over this but add a third ability to all towers because they just feel like their lacking in abilities.
4. Bring the gem shop to these games it would make the experience also more fun I know it is a mobile exclusive but they were fun on mobile.
5. Make the screen scrolling feature to right click instead of left click because its very irritating sometimes trying to navigate and accidentally selecting heroes and units and what not.
If you do these things this game will succeed massively
There is already some features you added I enjoy. So keep up the great work.