One dev's seven-month journey to build a NES emulator from scratch

A solo developer has completed LucyNES, a Nintendo Entertainment System emulator written entirely in the Odin programming language. The project, begun in mid-2024 and wrapped up in January 2025, took seven months of part-time work. The developer detailed the immense learning curve, covering the NES architecture, bitwise operations, CPU instruction cycles, and the intricate timing required between the CPU and the graphics unit (PPU) to achieve playable accuracy.

The emulator now supports hundreds of games, including the notoriously difficult-to-emulate Battletoads, and features a debugger, save states, controller support, and multiple cartridge mappers. The creator emphasizes that while getting a basic emulator running is possible relatively quickly, achieving the final 10% of accuracy for all edge cases is a monumental task that demands deep, sustained effort. This project stands as a testament to the dedication required for low-level systems programming and emulation development.