The latest patch for Costume Quest contains two significant changes:
– This fixes an occasional but serious crash bug, which was causing the game to write off the end of a mis-sized vertex buffer
– You can now disable vsync through the command line option -novsync. To set this through Steam, right-click on Costume Quest, select Properties, click Set Launch Options…, and enter –novsync. We’ll be adding this to the display settings UI in the near future.