Jupiter Hell is a roguelike I'm following with great excitement, it's serving a the spiritual successor to DRL (previously DoomRL, now called DRL since ZeniMax flexed their legal muscles) and it's looking good.
Good Company, a business management tycoon sim is a recent discovery and it will be coming to Linux. It looks stylish too, so hopefully it will be good.
Kingdom Two Crowns, the third in the Kingdom series released recently for Windows and Mac. It looked like we weren't getting it, but it's now confirmed to be coming.
Metropolisim from developer Halfway Decent Games is releasing next year, with a pretty bold aim to be the deepest city-building simulation experience ever.
While not as popular as it once was, Ballistic Overkill is still a reasonably good online shooter that I've spent a lot of time in. The latest update sounds quite amusing.
Easily one of the best and trickiest platformers around, Slime-san is a seriously underappreciated gem. Another big update recently released, adding in a level editor.