I use <path_to_d3_exe> -launch -w
-launch bypasses the launcher; if you dont have internet, you wont be able to launch the game without a shortcut with this
-w (windowed)
-test and -perftest make the game window gray forever
-launch bypasses the launcher; if you dont have internet, you wont be able to launch the game without a shortcut with this
-w (windowed)
-test and -perftest make the game window gray forever