God of Thunder was released on Steam on November 14th, 2017. It is completely free to download and play.
The hint book and manual are included in the download, and can also be viewed from the store page. The hint book is listed as the "Quick Reference" on the store page.
There is a full walk-through on YouTube that someone did a few years ago, as well as the soundtrack.
Press Alt-Enter in game to go full screen.
Walk-through (with commentary):
https://www.youtube.com/watch?v=yZ2AOkpYVlg&list=PL14B96FBC38C77A08
Walk-through of part 1 (no commentary):
https://www.youtube.com/watch?v=Kzsw3TLQ_4w
Soundtrack:
https://www.youtube.com/watch?v=_0xaKAzHCyE&list=PL8655A0E51876EA03