Wow... i´ve been hooked on this version now... I´ve never played the extra modes before...
(After awhile, you kinda forget about the lighting problem, even more at night stages)
Anyway (In case anyone was wondering or interested in the .dat files)...
I found a tool that can be used to open(and maybe repack) the .dat files.
http://www.emit.jp/gca/gca.html
Download "gca_v09k.exe" and install/extract
Make a copy of file, rename the copy´s extention from .dat to .gca. Run "gca.exe". Click the first tab, and select the third one down. Find the renamed archive files, click ok/open and then in next window click OK and wait for it to extract it all!
Been looking thru these for alittle bit and i noticed alot of .tga .ogg(well, yeah), .bmp and then a few more extentions that i don´t know...