Some time ago I made a video on some soundtracks that sound like some others (hopefully unintentionally, hence the mention to cryptomnesia). Was never able to share it around a lot, so I though what better than a forum with music oriented people to tell the similarities.
Let me know what you think of those, specially the Jason Graves case (Dead Space). Did he ever mention anything about it? (I know Christopher Young was among his influences). All four cases mentioned in the video were found by me while watching movies, playing games, etc.
EDIT: Oh, btw, the Billy Joel part got muted for copyright. There's a link to the song in the description of the video anyway, or you can google it.