The reason the Sega Collection was mentioned is that it's possible to get two plats from it if you play the US version and the PAL version, since they are counted as two completely separate games. I doubt this is the case with Demon's Souls and I don't even think Aquanaut's was released outside of Japan. Just mentioning that, and that's all I'm saying on the subject.
In other news, I finally managed to get the gold medals for all of the stages on Tornado Outbreak, so I should only have the collectibles left with possibly one odd or end leftover. I should hopefully plat the game either today or tomorrow, then I can move on to probably Borderlands or Demon's Souls (or I might go back to one of my older games).