An explanation of Halloween Harry vs. Alien Carnage

Halloween Harry was written by SubZero Software, located in Australia.
Apogee is the game's distributor.  In October of 1993, Apogee released
v1.1 of Halloween Harry in the United States.

As with Wacky Wheels and Mystic Towers, version 1.0 of Halloween Harry was
actually an incomplete version of the game released to a magazine in the UK.
The first complete, public release of Halloween Harry was version 1.1.

A month later, v1.2 of the game was released.  A year after that, Apogee
suggested a title change to "Alien Carnage."  SubZero agreed.  Thus, in
early November of 1994, "Halloween Harry" was dropped from Apogee's
distribution, and "Alien Carnage" added.  Alien Carnage v1.0 is essentially
Halloween Harry v1.2 with a name change, price change, and episode
reorganization.  The shareware version of Alien Carnage (its first episode)
is Halloween Harry's episode three.  With the exception of this
reorganization, Alien Carnage consists of the same episodes as Halloween
Harry.  The shareware version of Halloween Harry is still legal to
distribute; however, Apogee prefers you distribute the shareware version of
Alien Carnage only, as this version has the new pricing information
screens.