Spectrum Gem is a puzzle platformer for 8-bit Atari XL/XE computers, originally developed for the ABBUC Software Contest 2026. Inspired by the classic MS-DOS title Quadrax, the game combines brain-teasing puzzle mechanics with technical graphical innovations built specifically for Atari XL/XE hardware.
Gameplay & Mechanics
In Spectrum Gem, the goal is to navigate two characters through intricate levels, collect 4 gem shards, and reach the exit.
Key Features:
- Single-Player & 2-Player Co-op: Play solo by switching between characters on the fly, or team up with a second player in local co-op mode using two joysticks.
- Identical Abilities: Both characters can walk, climb blocks, jump off ledges, push blocks, toggle switches, activate teleporters, and ride elevators. Characters do not block each other, allowing seamless movement through tight spaces.
- Puzzles & Traps: Levels feature hidden hazards and interactive mechanics where players must determine which switch controls which mechanism. If either character dies, the level restarts.
- Joystick Controls & In-Game Menu: The game is fully playable via joystick. In 1-player mode, holding down the fire button switches control between the two characters. Holding the fire button longer opens the in-game menu, allowing you to restart the level, toggle between 1P/2P modes, or quit to the title screen. Keyboard input is only required when entering level passwords.
- Password System: Progress is tracked via a level password displayed on the status bar, allowing players to resume gameplay anytime from the title screen.
- Complete Ending Sequence: Includes a dedicated victory ending upon completing all levels.
Technical Highlights & Credits
Spectrum Gem was coded entirely from scratch, featuring graphics and custom level designs created by MatoSimi, with player animations designed by Tix, a status bar interface by PG, and an ATR disk image using the xBootDOS loader by XXL.
- Custom DLI Kernel: Uses a custom graphics mode capable of displaying 8 colors in low-resolution character mode, with up to 6 colors within a single character space.
- Fluid Animation: Features nearly 200 custom character animation frames.
- Debut of ALPA Mode: The title screen and victory finale feature interlaced images displayed in my custom-developed ALPA mode, used for the first time in this title.
- Hardware Requirements: Runs on a stock 8-bit Atari XL/XE computer with 64KB RAM (no memory expansion required). Supports optional stereo sound setups.
Origin & Quadrax Connection
Spectrum Gem was created with written permission from the original Quadrax creators, Marián Ferko and David Durčák, permitting the use of the Quadrax name and original level designs.
This release features custom level designs created specifically for Spectrum Gem. Conversions of original Quadrax levels are planned for future game iterations.
