It’s a good day to be a strategy gamer, as two PC classics have been made available for free by their publishers for a limited time only.

First up, System 3 is offering the original version of Constructor for free via GOG.com in order to promote the upcoming HD remake of the game. If you’ve not played it before, the game involves trying to monopolise local construction work by building properties and facilities, as well as sabotaging your opponent’s buildings with undesirable elements such as hippies and the mob. To claim your copy of the game, click here to visit the Constructor Facebook page (don’t forget to give it a like) and follow the instructions in the top post. This offer expires at 2:59pm CET on 1st February 2017.

Secondly, 2K Games is offering UFO: Enemy Unknown under its American name X-COM: UFO Defense. This one’s free as part of the Humble Store sale. This strategy classic from Julian Gollop sees Earth under attack from alien forces, and it’s up to you to command X-COM operatives in battle to repel the invasion. To claim your copy of the game, click here to visit the Humble Store and follow the on-screen instructions. This offer expires at 6:00pm GMT on 1st February 2017.