They’re also offering another two games for free if you log into the front page of the store on 3 and 5 separate days up to May 17. I set up a browser on a computer I don’t use to refresh the page once a day.
The 5 day one looks pretty neat. And the all-time reviews (not just the ones in the past month) are all mostly positive.
Stories: The Path of Destinies is free on Steam. Not sure for how long. I know absolutely nothing about the game but it looks nice and has a favorable impression from Steam users FWIW.
The “news” portion says through the 13th. Steam usually flips its deals at noon CST so I would try to get it before then on the 13th rather than assume it’s until Sunday night.
Galactic Civilizations 2 Ultimate free to keep on humble bundle.
Free weekends for Rainbow 6 siege and Shadow of Mordor 2 on steam.
Tides of Numinera is also having a free weekend - missed that one because it’s not really displayed on the front page.
If you visit the humble store once a day for the next 3/5 days you get free AI War: Fleet Command and 12 is better than 6 respectively.
Big Paradox sale on Steam right now, with a lot of DLC packs bundled and discounted.
Prismata is free for keeps on Steam until Monday
Unreal: Gold is free on GOG for the next 40 hours or so.
I didn’t play it when it first came out; I seem to remember trying but not getting very far. My hunch is that I couldn’t run it sufficiently so gave up.
Tried to play this one, but the mouse controls are super inaccurate and mushy. Played around with some setting but they didn’t seem to help much. I’ll have to revisit it later once I’ve caught up on my small backlog.
Distraint: Deluxe Edition is free on Fanatical
Fanatical used to be called Bundlestars and has been around for a good while and is an authorized key seller. They’ll probably ask you to link your Steam account which is safe and is just done so you can one-click redeem keys to your Steam account rather than having to copy and paste them. It doesn’t allow them access beyond that.
All Raiders of the Broken Planet campaigns are free to keep on Steam until Friday.
I don’t really know anything about the game but it looks as though the base game is Free to Play but the three campaigns are $10 each ordinarily.
God damn you to hell.
Also free on Steam. I was really doing well today, getting lots of important stuff done, but now I’ll probably play this the rest of the day. Or week, since it includes a lot of new levels. I had a lot of fun with the original 20 years or so ago.
Yeah, the stock version doesn’t work great with newer PCs. When I tried it, it was way too dark and jerky. It will run much better on modern PCs if you install the 227 patch from here:
https://www.oldunreal.com/oldunrealpatches.html
In the name of the Tsar DLC for Battlefield 1 is free. They had the first expansion free a few weeks ago. They’ll probably have the others free over time. Keep an eye out.
Galactic Civilizations II: Ultimate Edition is free to keep on Steam until Saturday.
HackNet Deluxe is free on Humble.
It’s been a good week or two for free games, I guess.
Steam is having a free weekend for:
Dead by Daylight
Cities Skylines
Don’t Starve Together A New Reign
Dirt 4
Left 4 Dead 2
Tyranny
Borderlands 2
Shadow of Mordor
Castle Crashers
Guns of Icarus: Alliance is free to keep on Steam through Memorial Day. You play part of a 4-man crew on an airship doing battle. Has PVP and PVE Co-Op modes and AI bots in case you can’t find three friends and hate playing with randoms.
Fun little game ! Reminded me of my comp-sci major days. It’d been a long, long while since I hadn’t dicked around w/ a Unix shell terminal 
Xenonauts, a modern recreation of the classic XCOM experience, is free today on GOG.
For Honor starter edition is free this week via Uplay.
GOG changed the free game to Ziggurat