Why do people still search for in 2025, over a decade later? Because progress is not always linear.

: You must use a ROM file specifically audited for the 0.139u1 set. Using a newer ROM (e.g., from a 0.200+ set) will often result in a "missing files" error.

To play Metal Slug 6 using the MAME 0139u1 ROM, you'll need:

: MAME 0.139u1 is based on the MAME 2010 romset. Users often find that the Atomiswave ROMs require a separate BIOS and specific file formats (like .lst and .bin ) that are difficult to run on older mobile-based MAME ports.

Is Metal Slug 6 on MAME 0.139u1 still relevant in 2025? For everyone else, use MAME 0.260+ or Flycast.