Go to Options > Input Config . MUGEN is notorious for needing manual mapping for Xbox or PlayStation controllers.
SNK vs. Capcom Ultimate MUGEN 3rd Battle Edition V30: The Definitive Download Guide Go to Options > Input Config
The V30 update specifically fixed many of the crashing issues found in V20 and added "Intro" and "Ending" sequences for many characters, giving it the feel of a finished, retail product rather than a hobbyist project. Go to Options > Input Config
Often, the best way to find the most "up-to-date" V30 patch is via MUGEN showcase channels. Look for videos with high view counts and positive comments regarding the "V30" or "V30 Plus" builds. How to Install and Optimize Go to Options > Input Config