I think he says "you're going down" just before kicking their asses some more, but then at the very end I don't know what he says... sounds kind of like "just enough" or "dust to dust"
Also something else to realise, for some people who haven't grasped the whole japanese nero / nelo thing... if you look at that translated page, you will see that the symbol for Nero's name gets translated into NELLO. That's because there is no such thing as 'R' in Japanese, there is just one symbol for L and R combined, there is no distinction. So to a Japanese person, writing in Japanese, Nero = Nello / Nelo. I don't really mind if people don't want to see that connection, however to me it's obvious. In DMC1, Nelo Angelo is the same as Nero Angelo. The reason why it isn't "Angero" is because the whole point is that it came from Italian, and "Angelo" is Italian, as is "Nero". But "Nelo" isn't even a word, it is more likely to just be an error, since "Nero Angelo" actually means something, and "Nelo Angelo" doesn't.