The game was fun but it needs more stuff, both combat and surroundings, otherwise it gets old pretty fast. Civilization might give you some ideas, especially with the unit diversity. Would love to see units like horse carriages and catapults. Also you need to differentiate more between units that are out of turns vs those that still have turns. Maybe an outline or a glow? Something that catches the eye.
For me, the best strategy was about 50/50 split between cheap units and archers. This helps most of the time except of the times when the enemy zerg rushes you with cheap units.
This game has a lot of potential, looking forward to seeing more in the future.