An in-progress decompilation of Mario Party 4 for the Nintendo GameCube that started in November 19th, 2023.
The project, found here, currently mainly supports USA release pre-patch (GMPE01_00), but also all other versions: the patched USA release (GMPE01_01), PAL pre-patch (GMPP01_00) and patched (GMPP01_02), and the Japanese release (GMPJ01_00).
It currently has the most fully linked code so far, primarily because the original game was released without optimization.
Mario Party 4 shares some code from the previous Mario Party titles, mainly in the engine. However, most of the code is completely new, especially within the minigames themselves.