[Update]: The free game of the day is now the rather atmospheric indie action-RPG Hyper Light Drifter.
The Epic Games Store is currently having a massive Winter Sale, and in order to attract as many eyeballs as possible, they've also been running a massive giveaway alongside it. Until January 1st every single day will bring with it a brand new free game, and as you might imagine, today's offering is the somewhat older indie classic FTL: Faster Than Light.
To claim your copy all you need to do is head over to FTL's store page, log into your account or create a new one, and you'll be ready to explode over and over again in no time! Speaking of which, you might want to hurry up as this offer will only be available for the next four or so hours, after which FTL will be replaced by a different game.
FTL is nearly a decade old at this point so chances are you already know what it's about, but if this is your first time meeting it, let's just say that FTL is a fun and highly replayable roguelike with a rather brutal difficulty curve. You will die, and you will die a lot, but don't let that discourage you as FTL is more about the journey than the destination. It's all about the strange stories that happen along the way, as well as the ridiculous events that will either help you or set you back so far you'll curse at space-spiders forever more! Either way, it's certainly a game you should at least try once, especially now that it's free.
Have fun, and I'll leave you with one of the trailers for the Advanced Edition: