Game wont start

After clicking 'Play' in the launcher, the launcher closes then reopens to show the 'Play' button and the console saying:

Completely ignored arguments: [--nativeLauncherVersion, 1216]
[00:05:08] [Client thread/INFO]: Setting user: "My friends username"
[00:05:10] [Client thread/INFO]: LWJGL Version: 2.9.4

Then nothing happens,