Thronefall

Much like Grizzly's last game, Islanders, it's simple and accessible, but has a lot of replay value and quality put into it.

Also, if you like tower defense games, I strongly recommend No Creeps Were Harmed TD. It's twice the price of Thronefall, but it comes with 60 maps, a story mode, online co-op, all wrapped in this unique mechanic of building defenses in maps that bend and twist at angles for interesting positioning of shots and paths.

Thronefall's maps are also VERY well crafted, but there's only 6 at the moment. Quantity doesn't equal quality, but thankfully you don't have to play every map in NCWHTD to unlock them all. They unlock in groups, so you can avoid maps you don't like.