I forgot to tell you that MAME is running this way here:
I added all these for the .EXE shortcut, to make MAME work with this app for iOS:
Should something not be used for this? Because I am only using this way now.
As for the O2M emulator, it can be found here:
In this MEGA link I only included the version that worked for me, 1.01 (it's old, from 2002). For some unknown reason the last released (1.18) in the oficial site:
Isn't loading any game. Don't have a clue why.
I haven't included any BIOS or game in the MEGA link, so don't worry about it.
The problem with this O2EM emulator is that while it works, it lacks many options. I can't use fullscreen in my PC and could not configure my gamepad to work with it. MAME would be the perfect emulator to suit my needs, since it works in fullscreen mode and used my gamepad, at least for a few games.