Since the official McLeodGaming website typically hosts the latest "Beta" version (currently Beta 1.4 as of May 2025), you will need to look at trusted archives for the specific v0.9b files.
This version featured a roster that was a mix of official Nintendo characters and fan-favorite third-party picks that have since been cut or reworked.
Locate the downloaded file, usually with an .exe or .swf extension, and open it.
Three new playable characters were added: Marth , Zero Suit Samus , and Chibi-Robo .