There are eight documented versions of Oni's game data for Windows, not including the demo (seven language versions, plus the UK/US variant).
Listed below are the sizes of the game data files (.dat/.raw) along with their creation times (or rather the times when they were last modified).
A completion time preceded by "=" indicates that the .raw file was completed (last written to) less than a second before the corresponding .dat.
(Depending on the OS and/or DST setting at the time of the installation, the time stamps quoted below may vary, typically by ±1 hour).
A completion time marked in bold is the same as for the original US version, and indicates 100% identical resources (typically .raw).
A file size marked in bold is the same as for the original US version, and indicates a lack of structural deviations in the game data.
A file size marked in bold italic is the same as for the UK English version (if different from US), likewise indicating similar structure.
An underlined file size is much larger than for the original US version (this occurs only for the Japanese level0_Final.dat, due to fonts).
N.B. Game data aside, there are at least two distributions of the UK version, with an Oni.exe that either does or doesn't check for the CD - but accepts extended ASCII text in both cases (unlike the original US engine). N.B. The Chinese localizers edited the .dat files in-place and left the .raw files unchanged (except for level0_Final.raw, also edited in-place). This is why all the file sizes match and the .raw files are 100% identical.