Golden Balloon

What you need: A ROM of Diddy Kong Racing, either the US 1.1 or the European 1.1 release, dumped from your own cartridge. US 1.0, European 1.0 and Japanese ROMs are recognised and refused.
SHA-1 of a correct dump, by version:
US 1.1: 6d96743d46f8c0cd0edb0ec5600b003c89b93755
EU 1.1: b7f628073237b3d211d40406aa0884ff8fdd70d5

Golden Balloon is a source port of Diddy Kong Racing for Windows, macOS, Linux and web browsers, built from the community decompilation. The game is compiled for your machine rather than emulated.

It adds widescreen with the original field of view, frame limits up to uncapped with optional motion smoothing, local multiplayer for up to four players including a shared Adventure Party mode, beta online races for two players, Taj, Wizpig and Terry as playable racers, and texture and music replacement packs. The European release keeps its original timing.

The download contains no game data. It needs Diddy Kong Racing US 1.1 or European 1.1, dumped from your own cartridge.

How to set it up

1. Download the build for your platform: a Windows zip, a macOS DMG, or a Linux AppImage or tarball.
2. Launch it. On macOS and Windows a file picker opens; on Linux, drag the ROM onto the launcher or paste its path. .z64, .v64 and .n64 all work.
3. macOS: the app is unsigned, so if macOS blocks it use System Settings, Privacy & Security, Open Anyway. Windows: if SmartScreen warns, choose More info, Run anyway.
4. Press F1 in game to pause and open settings.
5. Optional: create an empty portable.txt next to the executable to keep settings and saves beside it.