Thanks. The download certainly works without Steam as I haven't yet added any integrations. On release I'm considering my options for itch - perhaps something like a download key that will work without Steam.
I only mention Steam because I want to build wishlists there, and really I don't get a lot of itch traffic.
Edit - forgot the requirements.
The game should be playable on most recent Windows PCs - best experience is with a dedicated graphics card. A 1080 ti should be plenty to run it at 1080p/60 fps with ultra settings.