These are the major changes from standard distribution 1.3.3 to 1.4.0-A (the
A is for American, to distinguish from the European version):

British spellings have been changed to American, the most obvious example
being "armour."  This can be changed in existing files with the "fix_armor"
script.

The pub does not give out physical drinks any more, to prevent any
possibility of cheating.

There have been numerous spelling and minor bug fixes, much too numerous to
list here.

The player and soul programs have been rewritten, making them smaller.

A level system has been added for wizards to improve security.  New
invisibility levels have also been added.  See /doc/w/levels and
/doc/w/invis for more information.  A "promote" command has been added to
allow in-game management of levels.

A whole slew of new wizard commands have been added.  Type "help wizard"
inside the game for a list.  (This help lists only the commands which you
are of high enough level to perform.)

Cpp is now called through a pipe so that you can see the errors which the
precompiler returns.  Also, the routine used for opening the pipe is a
custom one (in vpopen.c) which doesn't glob or use sh for security reasons,
and which redirects both stdout and stderr.  This routine is also used for
ls now.

A % (modulus) operator has been added to LPC, along with %=.

A find_player(string) external function has been added to LPC.  This is just
like find_living() except that it will find only players, not monsters.
This was done by adding an "is_player()" function to player.c which returns
1.

The attack routines in living.h now call valid_attack() before allowing the
object to attack anything.  Valid_attack() routines have been added to
monster.c, monster.talk.c, and player.c.  The monster ones only allow a
monster to attack another monster if it has been specifically given
permission with "set_can_kill," another new routine described in
doc/build/monster.  Right now, the one for the player does not allow players
to attack novices, nor does it allow novices to attack other players.

The experience you get for killing monsters depends on your alignment.  The
bigger the difference in alignments, the bigger the ep bonus.  This
encourages a more consistent behavior pattern and adds to characterization.

Players can now have 1-line descriptions set with the "describe" command.

Death takes away only 1/4 of your ep.  Also, when you regenerate, it puts
you to whatever the appropriate level is for the number of ep you have,
complete with correct title and everything.

New level and alignment titles have been added, and the numbers have been
tweaked a bit.

Add_alignment in player.c has been modified to make it easier for lower
level players to build up an alignment.  Rather than losing 1/10 of your
alignment on each kill, you instead lose your alignment times 2/(30-level).

There are many more little changes, but these cover most of the important
ones.