ECM Games: Extended Colour Mode on C64

1 September 2022 · Updated 26 February 2026

Core Design Principles

Five fundamental guidelines shape modern C64 visual design, pushing beyond the typical 8-bit aesthetic:

Minimal multicolor mode — Favoring high-resolution or Extended Color Mode (ECM) for reduced pixelation. Multicolor mode’s 160-pixel horizontal resolution creates obvious chunky pixels; ECM provides full 320-pixel resolution with per-character color flexibility
Non-standard colors — Employing unusual palette choices through raster techniques rather than relying on dithering patterns that emphasize hardware limitations
Visibility — Ensuring clear separation between sprite elements and background layers through careful palette planning across all game states
Visual effects — Incorporating smoothing through color gradients, distortion effects for water and atmospheric phenomena, and layered scrolling creating depth
80-column fonts — Moving away from traditional chunky retro typography toward cleaner text presentation that doesn’t immediately scream “8-bit”

Historical Context

Extended Color Mode saw minimal use on the C64 historically, likely because developers prioritized multicolor mode’s familiar workflow despite its lower effective resolution. Rare exceptions like US Gold’s 1983 title Tapper demonstrated ECM’s potential, but the approach never gained mainstream adoption during the platform’s commercial heyday.

The demo scene sparked renewed interest in exploring underutilized hardware features, culminating in a dedicated ECM competition during late 2020. This event demonstrated that ECM could produce striking visuals distinct from typical C64 output, indicating growing enthusiasm among retro gaming enthusiasts for pushing beyond established conventions.

Notable Recent Games Using ECM

Quod Init Exit (Retream) — A platform game utilizing ECM to achieve visuals distinctly different from typical C64 output, with smooth gradients and clean edges uncommon in the platform’s library. Its sequel introduced a novel rendering approach with single reads and dual writes that optimizes ECM bandwidth utilization.
Goblin (Vanja Utne) — Demonstrates effective ECM usage with minimal chunky artifacts through careful color selection and tile design, enhanced by high-resolution sprite overlays that maintain character definition against busy backgrounds.
Robot Jet Action — Presents five distinct environments that highlight ECM capabilities across different aesthetic themes while using hi-res overlays to smooth sprite appearances and maintain readability during fast-paced gameplay.

Future Plans

Extended Color Mode will see expanded application going forward as more developers recognize its potential. The airspace display in Parallaxian already employs this technique for the instrument panel and status area, demonstrating ECM’s suitability for detailed interface elements. Ambitions exist for a complete ECM-based title in the future, exploring the mode’s full potential rather than mixing it with standard character mode.