NEMESIS 2 op flop

This forum is in English. As to your question, Konami originally released their games on Cartridge. But in 1988/89 Konami released some of the older games on disk, under the Konami Game Collection title. The Nemesis version you have is probably from this collection. Nemesis 2 and Salamander never got released on disk. Another possibility is that what you have is a hacked Brazilian edition of the game, which they "ported" to disk. Now Nemesis, Nemesis2 and Salamander are all MegaROM (128kB) games, so how come you can run Nemesis on a 64kB machine from disk? I did not look into it, but my guess is that it needs to load stages from disk, as required, to make it fit. Instead of loading the whole game into memory, as is typical for copied ROM games, which would require >128kB RAM in this case. This is how the hacked Brazilian edition worked, but that edition is supposedly pretty buggy and crashes before you can reach the end of the game.