As more games become available for Linux on Steam, I've been adding to my collection. Although I don't get much time to play, I like to support bringing titles to the platform with my dollars. Of the ones I have tried, the Wargame series by
Eugen Systems has been a standout.
Purchasing the trilogy during a sale, I started with Wargame: AirLand Battle due to it having a tutorial as a starting point. Going into this game thinking it was a more typical RTS, I quickly found out just tossing your units at the enemy results in a quick loss. The game has a dizzying array of units modeled on real world counterparts, and requires knowledge of how to use reconnaissance and correct unit selection and tactics. Unlike other games where one can just crank out more units if a strategy doesn't work, this game has 'decks' of available units. Just like in a real battle resources for each action are limited, and there's no time spent building bases and collecting resources.
In one of the tutorial missions I went in not realizing how the game works, and began to use the usual RTS tactic of building tanks then working my way up the map to clear each area in turn. By the time I got to the top, I had plenty of 'resources' (action points in this game), but was confused; why couldn't I build more tanks? By this time the AI was tearing my tanks to pieces with their air force and I was getting quickly overrun by their tanks. Reading more about why I lost and how the game actually works online, I tried another strategy next time; instead of wasting resources fighting battles that didn't matter, I flanked the enemy and cut off their air corridor. This time, with logical tactics, I won easily. I've been hooked ever since.