There's one thing I really did love about Sudden Strike 4, which was the singleplayer, so Sudden Strike 4: Road to Dunkirk actually sounds pretty good.
I came across HEADLINER today while researching more potential Linux games, this adventure game sees you controlling the news to further your goals. It might come to Linux, as the developer is looking into it.
Interstellar Marines was once an incredibly promising FPS, but sadly somewhere along the way they lost focus and funds ran dry. The last developer left has given an update.