Humble Bundle and GOG are doing a killer throwback
X-COM: UFO Defense is a real-time strategy with turn-based elements released in 1994. The success of X-COM has spawned spin-offs and "spiritual successor" titles, serving as an inspiration for the recent XCOM games, along with an unofficial sequel named Civ II: Fantastic Worlds, an expansion to the Sid Meier's Civilization II game. X-COM: UFO Defense is now free for a limited time over at Humble Bundle.
Constructor is a city building simulation which melds together strategy, humour and an occasional bribe of a city official or two. It's not your run-of-the-mill city building simulation as it includes taking out the competition's workers, stealing their assets and other shady "solutions" used by construction companies to get ahead in the business. Constructor is free for a limited time on GOG.