The free game Xenospore sees you try to stop the spread of a strange and deadly organism and there's a big upgrade out now. At a very basic level it sort of reminds me of Into the Breach because of the small tile-based world, and the alien stuff. It's very different though. Mentioned here on GamingOnLinux back in September last year, it's come a long way.
You go through 40 levels destroying world tiles to prevent the organism spreading, and then cleansing tiles that have been infected before they become food. It has some great looking pixel-art and the atmosphere on it is perfect. In the new 1.1 version out now the developer added in 15 new levels, 12 new tiles, improved graphics, new game mechanics, various improvements to the gameplay feel and more that you can see in the below video:
Quite a big fan of this one. Looking forward to seeing more from it!
Available with Native Linux support and it's free on itch.io.