Engine update

We've updated the game to the latest Unity engine 4.X version (4.6.8). This will address various platform specific issues (input, controller detection etc.)

For those who have controller issues: You can customize your controller setup in the input window pre-game. To open this window:

• On Mac: hold the options key while starting the game to open the setting dialog

• On Windows: hold the options key while starting the game to open the setting dialog

• On Linux: Add to the games launch options: -show-screen-selector