Directly downloading a "portable" iOS version is difficult because iOS does not natively support the M.U.G.E.N engine or APK files. Availability:

The build on iOS portable is a passion project’s dream and a casual user’s nightmare . If you love tinkering with virtual machines, optimizing config files, and building the ultimate crossover fighter in your pocket, you will find no greater joy. The ability to have Goku vs. Luffy on a subway ride, using a Backbone controller, is electrifying.

True M.U.G.E.N. was built for Windows. There is no official iOS app because Apple’s "closed" ecosystem makes running third-party engines difficult.

MUGEN was originally designed for . Porting it to mobile requires third-party adaptations. 🍏 iOS (iPhone/iPad)