The VG Resource

Beautiful Katamari's data has four .dat files (d02.dat, d03.dat, d04.dat, d05.dat) which store different types of information. So far, d04.dat is the most comprehensible file, as it contains easily editable stage data. Something to note is that within the game's files, d02.dat mentions the directory "F:\projects\KDX\", which I assume was used during the game's development, as keywords like "taikenban" and "test" appear alongside it. But the rest of these files are a mystery, so I request some help with analyzing them.

Thanks to the hard work of Katamari fans, heaps of unused content from Beautiful Katamari have been discovered! Using Ninja Ripper, Cheat Engine and editing the files, unused stages, graphics and modes have been discovered. However, there is so much more to be found within the game's data! 

The game uses the Intrinsic Alchemy engine by Vicarious Visions, which has a decent amount of documentation thanks to Alchemy 5's availability.

More information: In d02.dat, user Raccoon Sam was able to find some textures. These are probably related to some .tga files listed inside the file. Using programs like Dragon UnPACKer's Hyper Ripper haven't given any results.
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However, running the game's .xex file through one of these programs will result in Beautiful Katamari's icon and trophies being extracted as PNGs.
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I hope this extra information might help in figuring out this game's code!