After getting the second sword that can break walls (approximately one
third of the way through the game after the "Above the Bath's" area),
you will reach a large location where you must pass through a door with
Farah and activate a lever to open another door to a hallway filled with
scarabs. There are three positions to this switch (open door into room,
open door to hallway with scarabs, and open secret door to the classic
/Prince Of Persia/). The switch is located at the end of the room, near
the save point and near a large piece of rubble. There is a wall
opposite to that lever that appears to be unbreakable, and does not look
like other wall areas that can be manipulated. When you hit this secret
area on the wall, it will not spark as expected. After setting the
switch to unlock the door to the mini-game, keep hitting the
non-sparking section of wall until it breaks. A message will appear to
state that the original /Prince Of Persia/ game has now been unlocked.
Alternately, successfully complete the game.