GOG - one of our favourite online PC game stores outside of Steam - has just launched its annual Summer Sale, and it's a doozy. With more than 1,500 games discounted by up to 90 percent, it's the ideal time to expand your collection. 

Even better, this year GOG is offering one game entirely for free: if you pick up any game at all in the sale, they'll throw in a copy of Rebel Galaxy and it won't cost you a penny. 

The sale also sees the return of GOG Connect, which lets you link your GOG and Steam accounts together, and pick up free DRM-free copies of a selection of games you already own on Steam, including the likes of Downwell, Dropsy, and The Walking Dead: Season 1.

To celebrate all this good stuff, Tech Advisor has teamed up with GOG to pick out all of our favourite games from the Summer Sale. There are 36 games in our collection, ranging from recent indie hits like Little Nightmares right through to classic titles like the original X-Com.

You can browse the full Tech Advisor collection on GOG, or take a look at a few of our favourites right here. The sale is live now, and runs until 2pm BST on Tuesday 20 June.