DESIGN MODIFICATIONS

Some design modifications will be necessary or desirable during
development. The initial design might be too slow; an alternative
might make development easier or lead to a better game. They are
detailed here.


Mission Generation

An alteration has been made to the map generation algorithm. The
initial design disabled corridors and reduced possible room sizes to 1
in order to simulate corridors; this was done to ensure that
"corridors" were separated by doors. But this produces unattractive
level maps, so the default LevelMap settings have been reinstated:

* Corridor chances are left at their initial 50%. This will allow long
  and winding corridors to be generated again.

* Minimum cell size is left at 2, to ensure that rooms look like rooms
  and corridors look like corridors.

In enemy numbers, the existing design does not provide much variation
between easy, fair or hard missions. So the following rules will
instead be used for the generation of enemies:

* Easy: 2D6 are rolled, and the lower of the two dice is added to six
  to give the total number of enemy units.

* Fair: 1D6 is rolled and six is added to the roll to give the total
  number of enemy units.

* Hard: 2D6 are rolled, and the higher of the two dice is added to six
  to give the total number of enemy units.

Hostages are limited in number, such that the number of enemies and
hostages does not total more than 16. The number of enemies is decided
first, and hostages are reduced if their number exceeds this
limit. This allows a 16-bit field to be used to determine all units'
visibility.

Surprise Hostages: this element has been removed from the game as
adding unnecessary extra complication.

Enemy and Hostage units have their own classes. Basic stats start at
2/2/2, and are increased as per the other classes till their total is
21.  Enemy units have the same chance at armour that Auxiliary units
do; hostages start with no items at all.

Enemies have no primary skills; all points that would be applied to
primary skills are instead applied to secondary skills. Hostages have
neither primary nor secondary skills; all skills are chosen from the
tertiary skills table. The secondary skills for enemies are in the
following table:

	Roll	Chance	Enm
	2	1/36	HvF
	3	2/36	HvF
	4	3/36	HvF
	5	4/36	LtF
	6	5/36	LtF
	7	6/36	Bld
	8	5/36	UnC
	9	4/36	UnC
	10	3/36	Bld
	11	2/36	HvF
	12	1/36	HvF


Items are never initially distributed on the floor. The spare medikit
will always be put in a cabinet, unless there is no cabinet, in which
case there will be no spare medikit, in which case it will be given to
a hostage or random enemy unit. The adjusted table for the
distribution of data cards is:

	1: in a cabinet,
	2: in a cabinet,
	3: in a cabinet,
	4: in a cabinet,
	5: in the inventory of an enemy unit,
	6: in the inventory of an enemy unit.

Not distributing items on the ground obviates the need to calculate
line-of-sight for every item pile. Instead, any items dropped on the
ground will be considered visible, as (a) no items are generated on
the ground out of sight, (b) enemies and hostages do not drop items
till they are killed, so (c) all items dropped are done so within
sight of the player.

A spare knife is generated for every mission, and put in a cabinet. If
there are no cabinets, the knife is put into an enemy inventory. The
mission generator also ensures that one of the crew has a knife. These
measures ensure that there are knives for the freeing of hostages.


Player Unit Deployment and Movement

Doors do not block movement, but are automatically opened when a unit
enters the door square and closed when a unit moves away. This still
costs a single action point. This obviates the need to recalculate
lines of sight when a door is opened.

Encumbrance: the design specifies that the total number of action
points available should be reduced by the number of excess items
carried. This system makes encumbrance too light a burden, allowing it
to be largely ignored. Instead, action points remain at their normal
value, but every non-inventory action has its cost increased by the
number of items carried.

Furniture: moving through a square with a chair in it costs 1 extra
movement point. This gives chairs a purpose now that it is no longer
possible to crouch behind them.


Other Actions

Freeing hostages is not discuseed in detail in the design. Freeing a
hostage requires a blade in the hand, and takes six action points.


User Interface

The Map menu does not have the options "Open", "Close", "Crouch/Rise",
or "Skills/Items". It does have "Free", to free hostages, and "Next
unit", to select the next friendly unit that has action points
remaining.

The Main Menu screen is actually a New Game screen. Entering this
screen while in the middle of a game effectively ends that game. There
is no reason to come back to this screen during a game in progress, as
the original design seems to imply. The menu will be:

* Proceed: Start the new game with the team and mission settings as
  displayed.

* Scores: View the high score table.

Where in the original design there is a Main Menu option in most of
the menus, this will be replaced by the following two menu options:

* New Game: abandon the present game (if any is in progress) and
  proceed to the New Game screen. On screens other than Scores, this
  will require confirmation to prevent accidental abandonment of the
  present game.

* Exit Game: quit immediately. This will save the current game state,
  so that reloading the game will go immediately to the place where
  the player left off.

There are some screens not mentioned in the original design, but that
are necessary for the game. These are as follows:

The Victory Screen will congratulate the player, and summarise the
performance of the mission. A full list of each of the objectives and
scoring for that objective will be shown, along with the total
score. The menu will be:

* Scores: View the Scores screen (default).

* New Game: abandon the present game (if any is in progress) and
  proceed to the New Game screen. On screens other than Scores, this
  will require confirmation to prevent accidental abandonment of the
  present game.

* Exit Game: quit immediately. This will save the current game state,
  so that reloading the game will go immediately to the place where
  the player left off.

The Defeat Screen will tell the player that the mission has failed,
summarising the player's performance. A full list of each of the
objectives will be shown, although no score will be calculated. The
menu will have only the New Game/Exit Game options.

The Scores screen will show a table of 18 high scores: a column for
each of the difficulty levels, and a row for each of the mission
types. There will be a seventh row, an aggregate score for each of the
difficulty levels. The menu just be New Game/Exit Game.

The original design document forgets to detail what will happen during
the computer's turn. The display of the screen will be similar to Map
Mode, but the player will have no control.  The map will remain static
and not reveal the computer's moves, except where those moves are
visible to the player. The text output box will summarise what the
computer is doing, with a percentage counter periodically updated.

When a computer move is visible to the player, the moving unit will be
displayed. When the player is fired upon, a short animation (for want
of a better word) will be played, and a text message will be shown. A
similar animation will be shown when a player unit is able to use
opportunity fire.


Giving Medical Attention

Healing 1 point per attempt is too slow to be useful. Instead, healing
restores 1D6 points per attempt. In addition to this, unconscious
units who are healed to at least half their maximum hit points take
another endurance roll, and on success, are conscious again.


Surprise and Stealth

The original design suggests that a unit whose turn it is can be
surprised. This would be awkward to implement for the player. They
would ask "why can't I fire at this unit?", or if surprise prevents
thmm seeing the enemy, "why can't I move into this empty square?"

So the game will only implement surprise for units whose turn it is
not. Surprise will prevent the unit from using opportunity attacks.


Combat

The initial design doesn't specify an action cost for attacks. unless
playtesting suggests otherwise, a single attack should take six action
points.


Game Scores

Having time taken and health weighted equally with other scores allows
a player to achieve very high scores by doing the minimum effort:
killing one enemy, freeing one hostage or gathering one data card,
then getting out quickly and before losing any health.

To remedy this, scores will be weighted. Assassination, Hostage and
Retrieval do not need significant weighting, because "minimum effort"
is what is required: so scoring will be 40% health 60% speed.

Annihilation, Rescue and Gathering will reward players who genuinely
try to do as well as possible by weighting kills, hostages freed, or
cards gathered, as 60% of the mission score, while health and speed
gain only 20% each.
