In order to better handle move commands, refactor them out of the keyDown
event handler. This will enable using other input methods to trigger a move
command, such as mouse clicks or touch events.
An HN commenter noted that he ignored the mobilewarning and tried the game and found it worked. That is, until he got to the Embark stage and found himself arrow key-less. This warning is slightly more verbose to avoid similar situations.
Andrew Ardill