Xor must be revealed.

    !XOR

  His many faces are scattered through 15 levels.

Beware Xor controls his world and
doesn't give up his personality easily
XOR title and menu
Downloads
 
* XOR game (version 1.05)
   
* Level editor
   
* Hidden BBC levels
   
* XOR levels by David P
   

XOR Windows remake is freeware.
ovine by design