Summer is here! The birds are singing, there are leaves on the trees, everything is unbearably humid, and GOG's Summer Sale is back. Give up on the holiday—buy more games.

The headline discounts change every 24 hours. As I'm typing, The Witcher 3 is half off, classics from the X-COM series are 75% down and a big Star Wars bundle containing X-Wing, TIE Fighter and more is 60% off at £20.

You can also gain 'XP' towards free games by collecting badges. There's one just for having a GOG account, one for adding games to your wishlist, checking in every 24 hours, sharing the sale on Facebook... you know the drill.

For the next couple of days, there's also a free copy of System Shock 2 for anyone using the GOG Galaxy client.

The sale lasts until June 22, 12:59PM UTC, so there's plenty of time to make headway.