The Great Bigfile Hunt
Thanks to a lot of research, as well as the help of people like Andrew Fradley, Nex and SolidSnake11, Soul Spiral supports reading the data files for quite a few Crystal Dynamics games, including demos and prototypes. But "quite a few" is not the same as "all of them".
The goal of "The Great Bigfile Hunt" is to document every obscure release, demo, and prototype version of Crystal Dynamics titles that use the bigfile format, made from 1995 to 2005. Eventually, this will expand to include the entire Crystal Dynamics portfolio, but that will involve a lot more coding on my part.
How to Contribute
If you have any versions (demos and prototypes included, and regardless of platform) of the following Crystal Dynamics titles, and you haven't already tried to open the game's data file (usually BIGFILE.DAT, or PILL.BIG in the case of Blood Omen) in Soul Spiral, please do so.
If Soul Spiral doesn't recognize the game, pick the closest match from the popup list. If the file opens, go to the Export menu and choose Unknown Bigfile Data. This will prompt you to save a text file somewhere. Please do that, and send me the text file via one of the methods from the Contact page. Let me know which game it's from, the region it was released in (if applicable), and which platform it's for.