Simple game but nice idea, you definetly should extend/develop it further.

For example:

1) add ability to choose (on each base) type of units to build/spawn, stronger ones should take more time to spawn, some types should have advantage in combat against some other types, some sould have more damage or more health or faster traveling speed etc.

2) Add different factions with their specific perks

3) Add more enemy factions on the map, green, yellow etc.

4) Add ability to make alliance with 1 other faction, (for example you give them one of your bases (dots) and they can't attack you for, like, 2-3 min or so).

Would like to see this game grow))