Nebula 2.17 emulated it with adding a DAT file. ElSemi locked it in the newests versions of Nebula.
I don't like MS4 the worst game of the saga with difference! It seems a "copy-paste" game...
i got 2.17, and it took fucking forever to get the damn thing working with metal slug 4. Afterwards, i played it once for about 2 hours, after spending about 6 or so collective hours trying to figure out how to run it. It WAS NOT worth it.