Hello,
currently you are not able to play the game offline since it tries to download/verify the latest version of the spring engine on launch and exits with an error message stating that no connection to the server could be made.
I suggest not blocking the player out of the game but instead starting the game in an offline mode where logging in/multiplayer games arent possible. (which doesn't seem hard to implement since you can already play single player without logging in).
I never play multiplayer since I prefer being able to pause the game to give me time to think about my next move, also most players are too good at this game for me. Today I was looking forward to playing the game on my laptop at a place without internet connection and was sad that it couldnt work.
I like this game and would love to be able to play it at places with no internet connection.
Thanks for reading.