Games Republic is offering Anomaly Warzone Earth for joining. Just go to their site and register. 2nd click the follow email 3rd login on the site- go to profile then my games and download or can also request a steam key.
They offer a Linux,Mac, and Windows download.
https://gamesrepublic.com/game/strategy,anomaly-warzone-earth,123.html
SUMMARY
An extraodrinary twist of the tower defense genre that puts you in control of the armored convoy making its way through the heavily defended streets of a city captured by the alien invaders.
KEY FEATURES
Fast paced tactical battles pit your armored squad against enemy towers
Story driven campaign takes you through the ravaged centers of Baghdad and Tokyo
You control the Commander, a soldier physically present on the battlefield, picking up powerups and placing them
Resources gathered by the convoy on its way are spent on new units and upgrades - balance risk and reward when plotting the path