uchos: The one from the
Runic site should be Steam-free.
grinninglich: Are you sure?
I bought the game direct from Runic on Jan 3rd and there is no steam requirement. I paid, got my key, and used it to activate after installing the demo version. I would recommend you save the webpage after the sale though as I never got my e-mail with my key. I did get the paypal receipt though, so I can contact support with it if need be. You can also tie the key to a Runic Online account if you wish but I haven't done so yet.
The game did need a connection to activate but no other hassles beyond that. It comes with it's own launcher that will keep the game patched up if you use it to run the game. There is offline activation available, but you have to contact support regarding it.
https://support.runicgames.com/kb/articles/38-offline-activation