How to Make a Nintendo 64 Game in 2026: Inside Xibalba 64

In a detailed blog post, the developer behind the High Impact engine describes how a brand-new Nintendo 64 game, Xibalba 64, was built from scratch and released as a physical cartridge in 2026. Modretro, the company behind the M64 — a modern clone of the N64 — published the game as a launch title, complete with cartridge, packaging and manual.

A cartridge decades after the console's commercial life

According to the post, Xibalba 64 is only the second physical release of a new N64 game since the console's original commercial life ended. The first was Xeno Crisis by Bitmap Bureau, which reached the N64 in 2023; before that, no new N64 game had been published since Tony Hawk's Pro Skater 3 in 2002.

From a JavaScript engine to Nintendo's hardware

The project grew out of Impact, a JavaScript game engine written in 2010, and its C rewrite, High Impact. Because High Impact separates platform and rendering backends, a new backend for the N64 could be added without touching the rest of the engine. Building one on top of Libdragon — an open-source system library for the N64 — took only a few evenings. The post calls Libdragon "basically SDL for the N64" and a safer alternative to Nintendo's proprietary libultra.

Living with 4 KB of texture memory

The N64 pairs a 93 MHz MIPS CPU with a "Reality Coprocessor" that houses a fixed-function graphics processor (RDP) and a programmable vector processor (RSP). Texture memory is famously tiny — 4 KB, enough for 64×64 pixel textures, with painfully slow uploads. The developer batched triangles that share a texture into 64-bit draw calls, raycast 320 rays per frame to find visible level tiles, and used 4-bit indexed colours wherever possible. The result runs at a stable 60 frames per second, with four-player split-screen staying fluid. Sound and music take up about 31 MB of the 32 MB ROM, compressed with the 4-bit VADPCM format that Libdragon decodes on the RSP.

Shipping a game in 2026

Testing required real hardware: the Ares emulator models the RDP and RSP accurately, but the N64's slow memory bandwidth can only be measured on a console. The developer used a SummerCart64 flash cartridge, which uploads ROMs over USB-C during the build, plus a capture card to display video on his PC. Modretro answered his publishing pitch within a day, and the contract was adjusted to let the engine be open-sourced later. Sales, he writes, will not let anyone quit a day job, but should pay for "a few nice holidays".