After trying a number of things (including searching through
deassembled Marathon Demo CODE resources), I have found a fairly
simple solution to get the Marathon Demo to work on computers with
small screens.  It might cost you some money in the long run, but at
least it makes it possible.

Disclaimer: I do not endorse, condone, or even acknowledge ;-) this
method.  If your monitor or computer or little brother blows up
because of this method, remember that you took the risks youselves.  I
will not be held responsible for any damage caused by this method, nor
do I recommend using this method.


OK, that being said, on to the description.  I played the Marathon
Demo for a few hours last night on the 640x400 LCD screen last night,
and tried every level out.  The Marathon Demo played quite well,
although the lower 80 rows of pixels were missing (i.e. part of the
radar and part of the ammo/weapons list were off-screen).

Here's how I did it:

(1) Go to your local info-mac mirror archive.  In the "cfg" directory
    you will find a handy configuration utility named
    "mini-screen-171-demo.hqx".  Download and expand this utility.

(2) Mini-Screen is a little (and pricey!) utility that seems to cause
    your Mac to report a different monitor size than it really has.
    Supposedly this is to allow you to use smaller virtual screens on
    a big monitor.  The demo that is distributed has a built-in
    expiration date -- the real utility costs $39.95 (ouch!), and the
    demo contains instructions on how to order it.  Note that as
    distributed, Mini-Screen seems to have an expiration date well
    before 30-Nov-1994.  I had to set the date back on my Mac to even
    try the demo out.

    After you have unpacked mini-screen, install it according to
    instructions.  Basically, put the mini-screen control panel in
    your Control Panels folder and reboot.  (If mini-screen has
    already expired, then you will have to set your date back and
    reboot again to try it out.)  When your machine is up again, run
    the mini-screen control panel and manually type in "480" for the
    vertical size of the monitor.  (Note that the pop-up menu won't
    work for this purpose.)  Reboot again to get mini-screen to take
    effect.

(3) The Marathon Demo should now run.  >>>HOWEVER<<<, there is one
    more thing you will need to do if you want to be able to edit the
    keystrokes.  Run ResEdit (standard ResEdit disclaimers apply
    here!)  and find the dialog resource that defines the layout for
    the keystroke edit screen.  Open it.  "Select All" and move all
    buttons up to the top of the screen.  Close this when you are
    finished.

    The reason you need this step is because the "OK" button which
    lets you get out of the keystroke edit screen in Marathon tends to
    go way off a 640x400 monitor, leaving now way to get out of the
    dialog.  Fiddling with the resource as described above moves the
    button onto the screen (well, it does on my screen).

(4) Play Marathon!


This is all I had to do to get Marathon up and running.  Folks with
monitors smaller than 640x400 may need to do additional fiddling to
get everything to work.  Note that I know of no way to actually
reposition the screen elements in the normal game mode (i.e. the
weapons/ammo list and the radar).  If somebody knows of a way to do
this, then please speak up.

Also, if you plan to use mini-screen, then it is politic to pay for
it.  Alternately, if somebody knows how to cook up a small init or
control panel to cause a Mac to report a standard 640x480 screen,
please let me know or write a quick init to do this and distribute it.
I would do this myself, but I am not a Mac guru and do not know what
to fiddle.


Remember, your mileage may vary.  I hope this helps a lot of people
play Marathon who otherwise thought it wouldn't work on their machine.

-- 
 I hear the endless murmur,                               Christopher Lishka
   Every blade of grass that shimmers in the breeze       PPE Division, CERN
 And the sound that comes to carry me                    lishka@dxcern.cern.ch
   Across the land and over the sea.  -- Crowded House      vxaluw::lishka