But in the context of MIMK-070 , the "M" stands for or possibly "Monster" or "Male." The actual plot of the source manga (and thus the film) involves a cursed portable gaming device.
In video game history, "M Portable" means nothing. There is no console called the "M Portable." However, Japanese gamers and tech writers often shorten to "PSP" — never "M Portable."
But which manga? That brings us to the next part of the keyword. Before the "Vs M Portable," we have the core legend: Toire no Hanako-san (トイレの花子さん), or "Hanako of the Toilet."