In that vein,
one particularly excellent old game that _can_ still be
 purchased in its original format is Dark Castle <http://www.deltatao.com/
 darkcastle.html>.  Delta Tao sells its Color Dark Castle for $32.  For an
 additional $5 one can upgrade* to the original black and white Silicon
 Beach version. 
Are you talking about the game where you run around a castle throwing rocks
at birds, rats and bats?  The one with *great* sampled sounds?! 
 
That's the one.
   *My word, not
theirs.  :-)
  
Sometimes the classics are better in black and white? :-)