
             BLITZKRIEG - Docs sheet for the 32k Apple ][
            Programmed by Mark Cross for Programma -- 1980
    Compiled by Paula (I also fixed hex typos in original Programma doc)
                               Rev.3/1981

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Cassette loading address from monitor:  200.4000R  then  800G to run.


GAME PLAY
---------
Use the paddle or keyboard to aim your anti-aircraft gun and shoot down the
enemy planes! Bombers and three kinds of fighters fly overhead. If a plane
flies into another plane's debris, it will explode. Some pilots are inept
and fly into other planes, causing you to gain points! And the debris from
that crash could gain you more free points! And so on...

The game ends when your gun runs out of bullets, or one of the bombers drops
a bomb close enough to your gun to blow you up.


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MEMORY USAGE
------------
$0000-0011 - Temporary storage
$0800-0B16 - Slightly modified Apple hi-res routines
$0B19-254F - Main program
$38D0-3FFF - Shape table
$4000-5FFF - Hi-Res screen memory


MODIFICATIONS
-------------
The game has several adjustments to customize it to each user. These have been
pre-set, but can be changed as discussed below. Do this for each change:

1) - Load the program.

2) - In Integer Basic (or the monitor), make the changes. The Blitzkrieg
     program occupies the same place in memory as Applesoft programs. It
     is possible to load, modify and run Blitzkrieg only if there is NO
     Applesoft program!

3) - Optional: Resave the new version of the game:

        To tape from monitor:  200.4000W
                    From DOS:  BSAVE BLITZKRIEG, A2048, L14336

           Run it with CALL 2048  -or-  800G from the monitor


SPEED
-----
The program asks you whether you want to modify some things before starting.
This gives you a chance to set the speed. Asking for speed 9 makes the game
run as fast as possible. It also makes your score higher.


COLORS
------
The background is originally black, and the scene is drawn in white. These
colors can be reversed when the program gives you a chance to make
modifications.


NOISES
------
The debris makes sounds as it flies through the air. This sounds like
cracking, buzzing, or a steady tone depending on the speed of the game.
The noise can be disabled by POKEing zero into locations 6960 and 6961
($1B30 and $1B31). Restore the noises with POKE 6960,48 and POKE 6961,192.


AMMUNITION
----------
The starting ammo is set at 100. It can be increased by POKEing a number
up to 255 ($FF) into location 3148 ($C4C).


NEAR MISSES
-----------
Some anti-aircraft shells have proximity fuses that explode if they get close
to a plane. The shells in this game have the same ability. If they get close
to a plane, then the plane will blow up. The closeness required is a number
in location 4064 ($FE0). This number is originally 5. It can be decreased to
1 for a hard game, or increased to 8 for an easier game.


NUMBER OF AIRPLANES
-------------------
A new plane is created about once every 32 internal program time units. The
frequency of new planes can be adjusted by POKEing a number into location
5419 ($141D). This number is originally 31 ($1F).

                     Try changing it to these numbers:

               7 ($07) = Four times the original number of planes
              15 ($0F) = Twice the original number of planes
              31 ($1F) = Original number of planes
              63 ($3F) = Half the original number of planes

Other numbers will make the planes come in irregularly spaced groups.


DIRECTION OF FLIGHT
-------------------
One-fourth of the planes fly from right to left, permitting collisions. You
can make all the planes fly from left to right by POKEing the number 224 ($E0)
into locations 5175 thru 5179 ($1437 thru $143B).

                        -= Individual Plane Speeds =-

        Plane Type                 Location          Original Speed
        ----------                ----------     ---------------------
        Rightward Bomber          5210  $145A    4
        Rightward Big Fighter     5218  $1462    6
        Rightward Med Fighter     5226  $146A    6
        Rightward Small Fighter   5230  $146E    5
        Leftward Bomber           5293  $14AD   -4 (Hex) = 252 Decimal
        Leftward Big Fighter      5301  $14B5   -6 (Hex) = 250 Decimal
        Leftward Med Fighter      5309  $14BD   -6 (Hex) = 250 Decimal
        Leftward Small Fighter    5313  $14C1   -5 (Hex) = 253 Decimal


NUMBER OF BOMBERS
-----------------
You can control the types of airplanes using the "M" option when the program
starts. Bombers are very easy to hit, but too many bombers will make it hard
to avoid getting bombed.


NUMBER OF BOMBS DROPPED
-----------------------
A bomb is dropped by some bombers every 4 program time units if there is a
bomber on the screen. This can be changed. POKE a new number into location
5338 ($14DA). The number is 3 originally. A larger number will get you fewer
bombs. The number POKEd into this location must be a member of the series
3, 7, 11, 15, 19, 23, 27, 31,... Example: POKE 5338,255  ($14DA w. $FF) will
nearly disable the bombers for a young child who can't take the tension in
the original game.


DEBRIS
------
Sometimes the screen gets too full of debris. The amount of debris per ex-
plosion is controlled by the number 254 ($FE) stored in location 6174 ($181E).
Less debris would make a faster game.

               252 ($FC) = No debris at all
               253 ($FD) = 5 dots per explosion
               254 ($FE) = 10 dots per explosion (original game value)
               255 ($FF) = 15 dots per explosion
                 0 ($00) = 20 dots per explosion
                 1 ($01) = 25 dots per explosion
                 2 ($02) = 30 dots per explosion


HIGH SCORE
----------
The previous high score is stored in locations 2901 and  2902 ($B55 and $B56)
inside the program code. It is automatically saved along with the program. If
this number ever gets impossibly high, you can reset it. The simplest reset is
to POKE a 0 into both locations 2901 and 2902.



SHAPE TABLE
-----------
An Apple format shape table of 136 shapes is stored in locations 14544 ($38D0)
through 16383 ($3FFF). The shapes are listed below. All of the printing
characters (1-8, 21, 32-127) are in a 5x7 matrix with the shape starting at
the upper left corner of the drawing. The other shapes start drawing in their
center.

  Shapes
  ------
     1 - Box - 5 wide x 7 high
     2 - Solid 5x7 rectangle - draws black to erase something.
     3 - Arrow - Upper right
     4 - Arrow - Straight up
     5 - Arrow - Lower left
     6 - Arrow - Upper left
     7 - Alpha
     8 - Arrow - Straight left
     9 - Rightward bomber
    10 - Rightward big fighter
    11 - Rightward medium fighter
    12 - Rightward small fighter
    13 - Leftward bomber
    14 - Leftward big fighter
    15 - Leftward medium fighter
    16 - Leftward small fighter
    17 - Airplane seen from above #1
    18 - Airplane seen from above #2
    19 - Airplane seen from above #3
    20 - Very small tank (can be magnified and rotated)
    21 - Rightward arrow
    22 - Slightly larger gun
    23 - 2x2 square
    24 - Plus
    25 - 6x6 diamond - solid
    26 - 7x7 ball
    27 - Tie Fighter
    28 - X-wing fighter
    29 - 5 unit horizontal line
    30 - 5 unit vertical line
    31 - 6 pointed star (explosion)
    32 - Blank space

               - ASCII Characters -

    33 - !            69 - E             105 - i
    34 - "            70 - F             106 - j
    35 - #            71 - G             107 - k
    36 - $            72 - H             108 - l
    37 - %            73 - I             109 - m
    38 - &            74 - J             110 - n
    39 - '            75 - K             111 - o
    40 - (            76 - L             112 - p
    41 - )            77 - M             113 - q
    42 - *            78 - N             114 - r
    43 - +            79 - O             115 - s
    44 - ,            80 - P             116 - t
    45 - -            81 - Q             117 - u
    46 - .            82 - R             118 - v
    47 - /            83 - S             119 - w
    48 - 0            84 - T             120 - x
    49 - 1            85 - U             121 - y
    50 - 2            86 - V             122 - z
    51 - 3            87 - W             123 - {
    52 - 4            88 - X             124 - Vertical line
    53 - 5            89 - Y             125 - }
    54 - 6            90 - Z             126 - ~
    55 - 7            91 - [             127 - Left arrow
    56 - 8            92 - \             128 - Small 4x4 ball
    57 - 9            93 - ]             129 - 7x7 open circle
    58 - :            94 - ^             130 - 11x12 open circle (tree-top)
    59 - ;            95 - Underline     131 - Gun in airplanes game
    60 - <            96 - Single quote  132 - Race car #1
    61 - =            97 - a             133 - Race car #2
    62 - >            98 - b             134 - Bomb with partial tail fin
    63 - ?            99 - c             135 - Rocket
    64 - @           100 - d             136 - Falling bomb
    65 - A           101 - e
    66 - B           102 - f
    67 - C           103 - g
    68 - D           104 - h
