Hello.
Now Crysis is avaiable on www.gog.com without any protection (i suppose, it is the tradition of GoG). I suppose, also, that in the future people who bought the game on Steam might obtain a free copy through GoG Connect.
If you can wait, you can use GOG Connect which allows to freely activate a copy on GOG if you have a copy on Steam (https://www.gog.com/connect). They are limited-time offers, and for now no games can be imported.