Decompilation vs recompilation
Decompilation reconstructs source code from a compiled game. Static recompilation translates compiled instructions into code that can be built for another platform. Either approach can be part of a port, but the project's actual output determines what you can play.
A matching build can still target the original console
The n64decomp Super Mario 64 project documents a workflow that uses an original game image to build a matching ROM. A native desktop port has its own setup path. Check the repository you are following before treating a completed decompilation as a desktop release.
Recompilation also needs work around the translated code
N64Recomp translates Nintendo 64 code into C. Zelda 64: Recompiled combines that approach with the platform and rendering work needed for its Majora's Mask port. Its own instructions specify the required original game input and system requirements.
Check the release you intend to use
Look for supported systems, required original files and a release or build guide. If the repository only describes reconstruction or research, follow that workflow or look for a separate playable port. Completion percentages alone do not establish desktop compatibility.