GRAVITY BEAM: MASTER GAIDEN
---------------------------

2013/03/25 by Mathew Carr (aka MrD)

About
-----

Gravity Beam: Master Gaiden is a new game for the Sega Master System.


Story
-----

It is the 33rd century. Humanity continues its colonisation of the Red
Planet, Mars. Colonists and miners have worked tirelessly for many years,
excavating caverns of unimaginable scope throughout the core of the planet
in search of elusive subterranean minerals.

This devastating work is viewed with contempt by many fringe groups in
colonised space. Private security and intelligence forces are stretched
to breaking point protecting those trying to tame the Red Planet.

One group in particular, claiming to be allies of the 'guardian daimon'
of Mars, have struck many savage blows against the colonisation effort,
attacking mining facilities, dormitories, miners, engineers, scientists
and their families indiscriminately. They claim that the colonisation
efforts are causing irreparable damage to the natural ecosystem of Mars,
and demand that humanity leave at once.

Admist all this madness, a terrorist cell activates after a decade-long
infiltration into the heart of colonial governance. They take a number
of key colonisation personnel hostage. Their demand: the absolute
abandonment of Mars by the human race within twenty-four Earth hours.

The security forces deal with the immediate threat after a bloody and
protracted siege... but, with his final words, the leader of the cell
leaves a chilling warning...

"You may think you have won, but you can -never- win. We have planted a
nuclear device in the heart of Mars. A device capable of annihilating the
entire planet."

"The bomb is armed."

This is where you come in.

You are an ace pilot. The best. Your trusty ship, the Greenwing, is
equipped with a state of the art Gravity BeamTM, capable of hauling any
cargo through the most treacherous terrain.

With only minutes before the bomb detonates, you fly directly into
the caverns of Mars...

You've never had to carry a nuclear bomb before, but how dangerous can
it be?

Your mission:

* Negotiate the caverns of Mars and locate the nuclear device.

* Engage your ship's GRAVITY BEAM to attach the device to your ship.

* Carry it back through the caves and out into space, where it can then
be detonated safely.

GOOD LUCK, pilot. And GODSPEED.


Controls
--------

For the best game play, learn the different button functions before you
start.

Directional Button (D-Button): 
On the main menu, press up or down to navigate the menu options.
In-game, press right or left to rotate your ship clockwise or
counter-clockwise.

Button 1 or 2:
On the main menu, press Button 1 to select menu items.
In-game, press Button 1 to engage or disengage the Gravity Beam when
in range of the crate. Press and hold Button 2 to engage thrusters
and move your ship in its current direction.

The function of Button 1 and 2 can be swapped on the main menu.

Pause Button on the Power Base:
In-game, press to pause the game; press again to resume play.


Hints and Tips
--------------

Move slowly: the bomb is fragile!

Allowing the bomb to collide with the cave walls will damage it!
When the box starts blinking, you know you're in trouble. The box
will blink faster the more it is damaged. If the bomb incurs
enough damage, it will explode!

Even getting it caught on something may be enough to destroy it.
If the box gets stuck, detach from it immediately!

Remember your mission: don't place the box on the landing pad! We don't
want it!! You have to drag it out into space. To do this, fly your ship
out of the caves through the opening at the top of the screen near the
starting position while the Gravity Beam is engaged.

The Gravity Beam has a maximum distance before engagement. You can
only engage the beam if you're within about four ships' length of
the box.

The Gravity Beam has a maximum length during engagement. If the box
swings too far away from your ship, the Gravity Beam will be disabled
and the box will go flying across the landscape.

The box is pretty heavy; if you're moving at speed and you make a
sharp turn, the box might drag you into danger!

Your ship is indestructible, as are the cave walls. Colliding with
the walls brings your ship to a dead stop. Use this to your advantage.

The box falls rather slowly through open space.

While you're attached to the box, you will see a dotted line between
the Greenwing and the box.


Credits
-------

Game design and programming by Mathew Carr.
Music and sound design by Mathew Carr.
Graphics by Mathew Carr.
Compression tools by Mathew Carr.
Music and sfx player and module conversion tools by Mathew Carr.

Additional maths routines detailed in maths.z80asm

Cover planning by Mathew Carr.
Cover Greenwing illustration by Jonathon Carr.

If you'd like a 500 DPI printable full bleed version of the cover
to print out and put inside a real Master System keep case, I've
got you covered, just ask. :P

Tiled Map Editor (mapeditor.org) was used to create the levels.

Written in Z80 assembler.
Assembled using WLA Z80 Macro Assembler v9.5, written by Ville Helin.
Linked using WLALINK Z80 WLA Macro Assembler Linker v5.7, written by
Ville Helin.

Custom tools synthesized from the luminiferous aether as per requirement.

Many thanks go to the denizens of SMS Power, without whom this game
would not have been possible.

Emulators used:
Fusion (Fusion364): The Straightforward One.
Mednafen (mednafen-0.9.28-wip-win32): The Stark One That Does Rewinding.
MEKA (mekaw073, mekaw80): The One With The Cool Debugger.
Emukon (Emukon 1 05): The One That Simulates VDP Access Time Requirements.



Licence
-------

Gravity Beam: Master Gaiden, Copyright (c) 2013 Mathew Carr

All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.

* Neither the name of the author nor the names of the contributors may be
used to endorse or promote products derived from this software without
specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.