I have installed the RetroPie emulator, and start it with "emulationstation". It then loads up a graphical menu, where I can select all the ROM's for whatever console it supports, and play them. This is all fine and dandy, but when I want to power off my Pi I can't exit to the console (if that's the correct term), hence I can't type "sudo halt" and safely power down my Pi. I know that I can use ssh to remotely power it down, but I plan on making my Pi portable and so I won't have wifi or another computer. Is there a specific keystroke to exit the interface that I don't know about?