DMC 3 was a very hard game.
I don't know why, but when Capcom had the game released to the US and Europe, for some reason they changed our difficulty. Our "Normal" mode was actually Japan's "Hard" mode. So we were essentially playing on hard mode from the word go.
In DMC 3: Special Edition, they switched it back to our "Normal" mode was, uh, normal. So technically DMC3: Special Edition is easier than the original DMC 3.