These games all used to cost money but since then went free (which is why they qualify to be posted as a deal).
For better visibility (and since some of the games were posted a pretty long while ago) I am reposting them to draw attention to them, especially for the new users that joined Ozbargain since the postings.
All games are rated highly and definitely worth playing!
Crusader Kings II: https://store.steampowered.com/app/203770/Crusader_Kings_II/
You can still get a free DLC (Old Gods) for this game: https://www.ozbargain.com.au/node/528880
King Arthur's Gold: https://store.steampowered.com/app/219830/King_Arthurs_Gold/
NaissanceE: https://store.steampowered.com/app/265690/NaissanceE/
The Descendant: https://store.steampowered.com/app/351940/The_Descendant/
The Desolate Hope: https://store.steampowered.com/app/298180/The_Desolate_Hope/
Heroine's Quest: The Herald of Ragnarok: https://store.steampowered.com/app/283880/Heroines_Quest_Theā¦
Enjoy!
I can't speak for the others but Estranged Act I really isn't worth wasting your time on and it's been free ever since launch (as is Act II while it remains early access, so if you claim it now it will remain in your Steam library permanently).
I played through Act I pretty recently for the first time and found it to be a thoroughly dated game and not just because of the old Source Engine. The gameplay and level design is circa 2008-2010, and is reminiscent of equally now-dated, clunky and unpolished survival horror/exploration games like the Penumbra Series.
Things have come along way with titles like Alien Isolation, Outlast, Soma, Observer, Layers of Fear, et al.
For a solo project, it's definitely a commendable effort but there's so many more worthwhile horror, exploration and zombie games out there. Estranged just doesn't do justice to any of the genres/niches it's trying to fulfil; it's a case of too little, too late. Monstrum, Amnesia: The Dark Descent, Condemned: Criminal Origins and Alien Isolation are what you want to be playing to scratch that exploration/horror itch.