Thank you very much for your suggestings and information, Dr Jones and Starscream the 2nd!
Starscream the 2nd, your post was very usefull, thank you very much for taking the time to gather those games and uploading them for me. They were a very cool selection, I have tried them and they work really well
I didn't know that Doom games were only for PC-9821 machines. As far as I know, the original Neko Project II that I have ported, only emulates the PC-9801 ones. I will take a look to it...
Also, thank you very much for pointing at "Neo Kobe pack", I have been impressed by that emulators compilation and all the amount of work spent in it. And it is going to be very usefull for me too, to know if games that don't work in my port are due to a mistake in my porting process, or they don't really work in the original emulator.
Thank you very much!