A downloadable tool for Windows

NEShim

A Windows shell that wraps the BizHawk NES emulation core and exposes Steam SDK integration, allowing NES games to be published on Steam as native Windows applications — with achievements, overlay support, Steam Input, save states, and a configurable front-end UI — without modifying the ROM.

Features

Steam achievements — memory-watch triggers configurable per ROM hash; no recompilation required to add or change achievements for different games
Steam overlay & input — overlay pause, Steam Controller support via Steam Input action sets
Save states — 8 named slots plus automatic on-exit save; slot selection via hotkeys or in-game menu
Battery RAM persistence — save RAM written to disk on exit and restored on load
Configurable front end — main menu with custom background image, sidebar art, and looping MP3 music
Audio — volume control and optional sound scrubber for warmer playback on modern hardware
Graphics — nearest-neighbour (pixel-perfect) and bilinear (smoothed) scaling modes
Input — keyboard remapping and XInput gamepad support with configurable dead zone
Window title — set per-game via config.json; no rebuild needed