Free Hero Mesh

  ALT+G       Inspect globals
  ALT+P       Begin slow replay
  ALT+R       Select a unsolved level at random
  ALT+[       Increase slow replay speed
  ALT+]       Decrease slow replay speed
  INS         Toggle insertion mode
  DEL         Delete a move
  CTRL+DEL    Delete all moves forward

Mouse (in grid):

  MIDDLE       Describe topmost object
  RIGHT        Inspect objects (main world)
  SHIFT+RIGHT  Inspect objects (bizarro world)