ECON - Elemental Connection was quite a surprise, a puzzle game that can be played both offline and online that has you take it in turns to build a mosaic.
Note: Key provided by the developer.
For those who prefer their more relaxing experiences to other action-packaged options, ECON is a little gem. Honestly, it's nothing to look at and you could easily pass it up since even on Steam it doesn't have a single user review. However, it's actually a pretty good tile-matching puzzler.
Featuring simple gameplay that's really easy to understand, all you need to do is rotate the tiles you're given each time and place them on the board next to segments that match each tile to score points. There's a few ways to score extra points (and lose some) and so it becomes quite interesting as the board fills up. A very simple idea and the execution is practically perfect.
There's various different AI settings for those who don't have someone to play against online. From a relaxing "Creative" AI that only cares about matching tiles, to the "Efficient" AI that might just kick your butt.