Nice tower defense game, plus it has a consistent theme to it, which is always a plus.
If you plan on expanding the game, here are a few suggestions that may help:
- You can't quit a game after losing;
- Make the UI or circles on the ground in which you cannot build show for example a red arrow instead of a green one, and maybe don't show the UI with the towers options but rather a UI explaining why you can't build there and that you need ot "expand" first;
- Add quality of life features, for example the obvious "speed up" option to speed up waves of enemies;
- Add different types of "enemies", maybe not only ants (which could be varied adding red ants too for example), but maybe also spiders, scorpions, ecc... that have different stats, plus flying enemies that can only be targeted by some defenses (not by the AoE defenses for example) to add depth to the gameplay;
- Explore the possibility of having enemies come from all directions, so that you need to defend the flower at the center of your map and place flowers all around you: this will also give the player more spots to build new towers;
- Polish the game, adding some simple animations for both towers and enemies, adding sounds, adding maybe a skybox around the game's main plane, ecc...
Overall, good job on the game, keep it up :)