There are so many time periods with a plethera of mods to pick and choose. Commanding your own army can become a hastle but not if you have allies to fend off the invaders. Every country is playable.

For a free game, it can be very competative, This game has 7 nations to choose from and more flags for more nations. It can get difficult but that cant stop you from get to where you want with balance

With so many communities and plenty of servers with people playing through missions with whatever goal they have. Arma 3 has almost everything to offer and mods keep us looking for more battles.

This real-time strategy game is one of my favorites with intense missions and combat. It can take a while and a couple of tries to get the perfect outcome of a battle, but its not impossible.