This game is, while simplistic, incredible, in my view. The unit and structure progression is fine, and matches well with the difficulty climb.
My advise: A line of Pillboxes/Bunkers/Fortresses, backed by the faction equivalent of flak guns. Lots and lots of flaks. They work wonders on infantry and vehicles, they fire faster than dedicated Anti-tank guns, compensating for the lesser damage with raw fire volume, and they generally have greater range too.
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