Kaitei Attack + THE 0-sen (Tatsuya Watanabe)

Title – 海底アタック / THE 0せん (Kaitei Attack / THE 0-sen)
System – Sinclair ZX81
Author – 渡辺　達也 (Tatsuya Watanabe)
Publication – Micom BASIC (マイコンBASIC) November 1982
Page Scans – 1 2
Preserved By – TWE
Recommended Emulator – EightyOne

Download ROM

Loading the Game –

Files:
kaiteiat.tzx: Tape image of Kaitei Attack program
kaiteiat_en.tzx: Tape image of translated Kaitei Attack program
the0sen.tzx: Tape image of THE 0-sen program

NOTE: EightyOne emulates a wide range of Sinclair computers, so it must be configured to emulate a ZX-81, preferably with the 16K RAM expansion, since Kaitei Attack may run out of memory mid-game.
– Options -> Hardware -> ZX81 (on the Sinclair tab), select “16k” under “RAM Pack”.

Load the dowinski.tzx tape file, type J, Shift-P, Shift-P (the resulting output should be ‘LOAD “”‘), press Enter then play the tape;
NOTE: EightyOne does these steps automatically upon loading the tape image.

After the program finishes loading, press R (for ‘RUN’) then press Enter to start the game.

Game Instructions –

Kaitei Attack:
Launch the torpedo with [NEWLINE/Enter];
Kine up your shot to hit the warship’s control room(the topmost pixel).

THE 0-sen:
Move left with [5], down wth [6], up with [7] and right with [8], and fire with [A];
Drop your missile so that it hits the other one; You cannot be damaged by the other missile.

Article Translation –

ZX-81
Undersea Attack
THE 0-FIGTHER
Tatsuya Watanabe

Undersea Attack

How to Play
After doing RUN, A black warship will appear at the water’s surface. The score appears at the upper right. At the start you have 100 score. A torpedo will appear from the lower left and go from left to right.
Aim for the warship’s control room, and when it lines up directly below you, press the [NEWLINE] key. Upon doing so, the torpedo will start ascending from its current position. A clean hit at the control room will up your points by 50, whereas missing it even slightly will down your points by 20.

Program Explanation
1 -30 Warship and score PRINT
40 -80 Torpedo left-right movement and input handling
90 -120 Torpedo ascending movement
130 Collision handling
140 -150 Miss processing
160 -170 Hit processing
180 -200 Round processing

Variable Table
S……Score
A……Horizontal pixel coordinate
B……Vertical pixel coordinate

{Picture 1} Torpedo fired
{Picture 2} HIT!!

THE 0-FIGHTER

STORY
In World War II, Japan’s military had manufactured the invulnerable Zero figther. One day, the enemy forces staged a surprise attack. It is not known from where the enemy comes from. Skilfully piloting the 0-Figther, you shout “Now!” as you start firing your guns.

How to Play
After doing RUN, the Zero-Figther will start flickering. Afterwards, the position where the enemy’s missile is is drawn. Using the keys, fire your missiles to hit the tip of the missiles.

KEY Controls
[5] goes left, [6] goes down, [7] goes up, [8] goes down. Pressing [A] fires your gun.

Program Outline
1 -4 Enemy and Zero-Fighter starting positions
11 -50 Zero-Fighter movement
70 -76 Enemy movement
101 -106 Zero-Fighter position to bullet position exchange
112 Collision detection
113 -140 Enemy movement
150 -165 Bullet flight processing

Variable Table
A Zero-Fighter’s line
B Zero-Fighter
C Missile starting position(X coordinate)
D Missile starting position(Y coordinate)
E Bullet starting position(X coordinate)
F Bullet starting position(Y coordinate)
G Bullet exhaustion position(Y coordinate)
L Routine exchange

{Picture 1} Enemy missile spotted!
{Picture 2} Fired shots, doesn’t look like it hit

CHECKER FLAG:
Editor: We keep getting great Sinclair programs. Even though there’s only 2 here. However, these were easy to understand and therefore the most suitable for BeMaga.
Dr. D: Agreed. The article has entries on the program’s outline and varables, so I don’t have anything to say.
Editor: These programs are simple, so those typing them in should think of ways to make their own variations of them.

★Short programs are great! Long programs are a pain to input. (Asahikawa, Hokkaidō・Kazuo Kurosawa, 32 y.o.)……【Editor: I can’t understand long programs. I much prefer the short ones…】
★I’m very pleased with the Operation Port project. Please do the monitors and routines of the better models! (Tokushima・Manabu Kashiwagi, 32 y.o.)……【Editor: Certainly. Dr. D: Please wait a while more.】