Aliens is a horizontally scrolling shoot-’em-up arcade game written by Kristian Boisvert and published by Byte Power in 1986, targeting the TS2068. The player pilots a spaceship across a procedurally-rendered, jagged green terrain while engaging red alien enemies that emerge from the ground. The game features a scrolling starfield window at the top of the screen — a common split-screen technique used to suggest depth and motion — alongside a HUD displaying a six-digit score and a row of ship icons representing remaining lives. The title screen uses large custom-drawn block lettering rendered via PRINT statements or user-defined graphics, typical of BASIC or compiled BASIC titles of the era. Byte Power was a Canadian TS2068-oriented tape magazine that distributed original software and games to the North American Sinclair/Timex community.
Program Analysis
Overview
Aliens is a horizontally scrolling shoot-’em-up arcade game written by Kristian Boisvert and released in 1986 under the Byte Power label. Byte Power was a Canadian tape-based magazine that distributed original software — games, utilities, and applications — to the North American TS2068 community. The game’s title screen credits “© 1986 BYTE POWER” and identifies Boisvert as the sole author.
Gameplay
The player controls a spaceship that flies horizontally across a landscape. Key gameplay elements visible in the screenshots include:
- A jagged, mountainous green terrain rendered along the bottom of the play area, which the player must navigate without collision.
- Red alien enemies positioned on or just above the terrain surface, acting as ground targets to be destroyed.
- A scrolling starfield rendered in a bordered window at the top of the screen, providing a sense of motion and depth.
- A HUD at the bottom of the screen displaying a six-digit
SCOREcounter and aSHIPSindicator showing remaining lives as small spaceship icons.
Technical Details
The split-screen layout — a starfield panel at the top separated from the main play area by a horizontal dividing line — suggests the use of either display file manipulation or careful PRINT/PLOT positioning to create distinct rendering zones. The terrain is drawn as a filled polygon-style green mass, likely generated using PLOT and DRAW commands or a machine code routine to achieve smooth scrolling. The player sprite and alien sprites are rendered using user-defined graphics (UDGs), a standard technique for character-cell sprite work on this platform.
The title screen’s oversized “ALIENS” lettering is constructed from custom block characters, a technique frequently employed by BASIC programmers to simulate large display fonts without a dedicated font engine.
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Image Gallery
Source Code
Note: Type-in program listings on this website use ZMAKEBAS notation for graphics characters.