A fast shoot-’em-up: destroy the aliens, satellites, galaxies and robots that spin around the screen without being hit. Your ship turns left and right and thrusts forward, and once it starts moving it cannot stop until you reach a new level or lose a life. The default keys are Q (forward), O and P (turn left and right) and the space bar (fire); the keys can be redefined and a joystick can be used. The game shows lives, level and score, keeps a table of the five best scores with names, and has a title menu to play, view the high scores, redefine the keys or quit.
The title screen reads “©1987 Byte Power, written by Kristian Boisvert”. It was published on the Byte Power Spring 1987 tape (Issue 7), where the magazine calls it a fast-action shoot-’em-up and notes that on the Spectrum it takes a Kempston joystick.
Program Analysis
The whole game is machine code. The one-line BASIC loader (the stored listing below) sets black ink and paper and a black lower screen with POKE 23624,0, loads a 3,567-byte block at 50000 and calls it, then loads the 17,906-byte main block at 38779 and calls it; when the game returns it does CLEAR 65535: NEW. The code has not been disassembled here.
Notable Techniques
- Two-stage machine code load from a single short BASIC line, with the first block run before the main one is loaded.
POKE 23624,0(BORDCR) so the lower screen stays black while the code loads.
Image Gallery
Source Code
10 INK 0: PAPER 0: POKE 23624,0: CLS : LOAD ""CODE : RANDOMIZE USR 5e4: LOAD ""CODE : RANDOMIZE USR 38779: CLEAR 65535: NEW Note: Type-in program listings on this website use ZMAKEBAS notation for graphics characters.