I had no problems on win7 64-bit but running as admin and resolving compatibility issues worked for someone else: https://gtm.steamproxy.vip/app/797620/discussions/0/1728701877473364769/

Thanks, I already read that other thread but running the game as administrator does not help. Though I don't quite get the "resolve compatibility issues" part. I tried "Running this program in compatibility mode" (not sure of the title as I use a french Windows) and chose "Windows 7" with no success. Is this "resolving compatibility issues"?

not sure actually, just quoted the other guy. if you're running it on win7 anyway, don't know if setting compatibility to win7 does anything but you could try win xp compatibility both as admin and not, from steam and directly from the .exe, who knows. what might also work is verifying game files and restarting steam and trying again.

Hi. Sorry the game's not working for you. Is there a log.txt file in the game's folder that you could send me (ian@ianmaclarty.com)?

You could also try the direct3d version of the game (the default version requires opengl). You can try the direct3d version by choosing the direct3d beta (right click the game in your steam library and then click the betas tab).

Sorry, I got a refund, and deleted the game folder after uninstalling it, so no more log.txt. But iirc I opened it once, trying to figure what happened and read nothing more than the errors shown in op. I later thought that maybe it came from my Steam client being launched with admin rights ("Run as an admin" ticked in shortcut properties), generating those "Unable to initialize steam" messages. But that was too late to test.