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 ------------------------------------------------------------------------------ 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. ------------------------------------------------------------------------------ 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