The main challenge posed in translating the game SEGAGAGA, apart from the font width issue, seems to be the fact that most textures are stored in a compressed format and I haven't seen anyone online successfully able to decompress them.
These textures appeared to be stored in .MRG files (which are just the files in a row, with gaps of variable size). However, no PVR, PVR-X or any related tool (also tried Noesis and PuyoTools) seems to be able to open them.
Header example: left (uncompressed PVR file), right (compressed).
Based on my rudimentary knowledge, I guess it could be LZSS compressed but maybe the standard header info is omitted and hard coded elsewhere. Given discussion has come up on it years ago though, if it were that simple, I'd assume someone would have figured it out already.
So I suppose my question is - is there any clue on how to decompress these images?
Sample MRG file (contains a bunch of compressed PVRT files): https://vixyn.eu/file/_SG_LOGO.MRG
Sample uncompressed PVRT file which is readable by all tools: https://vixyn.eu/file/WOODBOX.PVR