Great game all around.
Fun mechanics, appealing artwork, fitting music.
An ability to hide merge/tech upgrades to review army before choosing would be nice.
Foot Archers are technically infantry, so inclusion or rewording to some upgrades that pertain only to melee units might be helpful.
These aren't complaints, just notes. The game is pretty sound as is and nothing stands out to me as broken or needing heavy attention.
Great job. Keep it coming. 👍