Spiders
Joe Rocke
A furiously fast and frenzied game, "Spiders" will keep your fire-button finger in top physical condition. It takes sharp reflexes and lots of stamina to resist the waves of alien spiders bent on attacking your solar system. Originally written for the unexpanded VIC-20, Spiders has been adapted for the Commodore 64 with joystick; Apple; IBM PC with 128K, color/graphics adapter, game port adapter, joystick, and Advanced BASIC (BASICA); and PCjr with 128K, joystick, and Cartridge BASIC.
The Arachnid Empire is invading, and it's up to you to stop them. These venomous spiders have left their home web-world to seek fresh prey, and are attracted to the blue sphere of Earth.
As you sip coffee in your comfy chair, you're suddenly interrupted by screaming klaxons and flashing lights which alert you that a large Arachnid armada is speeding toward Earth. It's too late to send up manned fighters, so you activate the planetary defense system—radiocontrolled robot fighters. No longer comfortable, you poise before your video screen, thumb on the launcher button, awaiting the onslaught.
Your video screen shows the spider formation. Three rows of fighting spiders jockey for position, hoping to receive the signal that will dispatch them toward glorious conquest. The whole armada sways back and forth hypnotically. Individual fighters get the signal and careen away, dropping missiles. You must position your robot fighter beneath each spider, then squeeze off a shot. Down they come, firing missiles as they whirl toward seeming victory. If you miss, the spider will rejoin its comrades. Their orders are to eliminate the planetary defense system (you), then attack en masse.
Two Arachnidan generals radio orders from their safe positions at the top of the formations. A lieutenant waits beneath each general. The generals and lieutenants won't attack until you've eliminated all the fighters, but then will fight with surprising speed and fury. Until you've destroyed the fighters, these officers are impervious to your attack.
You get 10 points for shooting a fighter in formation, and 100 points for an attacking spider. You have three robot ships available, one at a time. You lose a ship when a spider hits it with a missile or crashes into it. When (not if) you lose a ship, the invaders victoriously swarm to the ground.
The bonus round begins once you've eliminated all the fighters. Two at a time, the lieutenants and then the generals launch their attack. The bonus round scores ten times as much as normal play. Shooting an officer in formation gets you 100 points, and hitting an officer in flight is worth 1000 points. The bonus round ends when your ship is hit or when you've finished off the officers. You don't lose your ship if hit during the bonus round. After the round, a new (more difficult) formation appears.
VIC-20 Spiders
The VIC, 64, and Apple versions of "Spiders" each consist of two programs, one written in BASIC, the other in machine language.
Program 1 is the BASIC portion of Spiders for the unexpanded VIC-20. Program 2 must be typed in with "Tiny MLX," the machine language editor for the unexpanded VIC found elsewhere in this issue. Before typing in Program 2, make these modifications to the Tiny MLX program:
100 POKE55, 0 : POKE56, 25 : CLR : rem 8 210 S = 6405 : E = 7676 : rem 136
After you have typed in and saved both programs, follow these steps to load and run Spiders on the unexpanded VIC:
- Load the BASIC program (LOAD "filename", 8 for disk or LOAD "filename" for tape).
- Load the machine language program (LOAD "filename", 8, 1 for disk or LOAD "filename", 1, 1 for tape).
- Plug in a joystick and enter RUN.
Commodore 64 Spiders
The 64 version is entered much like the VIC version. Enter the BASIC portion (Program 3) and save it to tape or disk. Then use the 64 MLX machine language editor to enter Program 4. Use a starting address of 7911 and an ending address of 9182. To load and run Spiders on the 64, follow these steps:
- 1. Load the machine language program (LOAD "filename",8,1 for disk or LOAD "filename", 1,1 for tape).
- 2.Enter NEW.
- 3.Load the BASIC program (LOAD "filename",8 for disk or LOAD "filename" for tape).
- 4.Plug a joystick into port 2, enter RUN.
Apple Spiders
The Apple version works on the Apple II Plus, Apple lie, or Apple Ilk with DOS 3.3. The keyboard is used instead of the joystick. Press the space bar to fire shots and the left- and right-arrow keys to position your ship.
Type in the BASIC portion (Program 5) and save it to disk. Enter the machine language portion (Program 6) with the Apple's machine language monitor. Follow these steps:
- From BASIC, enter CALL–151. You'll see the asterisk (*) prompt of the monitor instead of the bracket (]) used by Applesoft.
- To enter each line, type in the address of the line (the four-digit number), then a colon (:). Use this colon in place of the hyphens shown in the listing. Next, enter the eight two-digit numbers, separating each with a space. Press RETURN at the end of the line, then enter the address of the next line, and so on.
- After you've entered the listing, press CTRL-C, then RETURN to exit to BASIC.
- To save the machine language to disk, enter this command, using the exact filename given here:
- To play Spiders, simply run the BASIC program. It will automatically BLOAD the machine language portion as long as the disk with "SPIDER 2" is in the drive.
BSAVE "SPIDER 2", A$9000, L$4C6
PC/PCjr Spiders
Due to programming considerations, the IBM PC/PCjr version of Spiders plays differently than the VIC, 64, and Apple versions.
Despite gallant efforts, the VIC, 64, and Apple players have let some of the invading spiders escape. Now the spiders are heading for the final battle, which takes place on your IBM. As mankind's last hope, you must thwart the ruthless aims of the Arachnid Empire. The evil Empire sends wave after wave of Spider ships with only one purpose in mind—get past your defenses and conquer. As the lone defender, you must not let these ships escape. Line up your craft beneath the oncoming horde and press the fire button on your joystick to send a pulse of energy flashing skyward. The alien ships will not fire, nor will they attempt to dodge your shots. They depend on their strength in numbers to defeat you. The dreaded arachnids do not fear death and will happily fall upon you, detonating both of you in a flash.
You get more points for shooting the aliens when they're closer to your ship. Therefore, shooting a spider can be worth anything from 10 points to 200 points. After all the spiders have either fallen or been destroyed, you get a 10,000-point bonus, but watch out—you lose 1000 points for every spider you let escape. If your score falls to zero, you lose one of your three ships, as if you had been hit by a falling spider.