Is it possible to play Magicka in LAN?

Most games that use Steam as DRM have been programmed to require authentication only once or once per update. Do you get the same message when trying to play a single-player game?

Have you tried the following procedure?

   1. Install magicka on all target computers. 
   2. For each of these computers; 
     a. Connect it to the internet
     b. Start a game.
   3. Repeat step (2) without being connected to the internet.  

The above method should function provided that the game is not coded to authenticate with each game connection attempt. If it is, you may have to circumvent the authentication procedure through directly modifying the game's code.

This may become necessary to get the netplay features of the game working in a future where the authentication server may become unavailable.