From the hex window that does not look like compression -- there an awful lot of large repeating fragments and runs in that. Even the most rudimentary schemes would catch a lot of those, and the PS1 was a bit beyond rudimentary schemes. I can't rule out the other files but that one at least does not look compressed.
Anyway what it sounds more like you are asking is what do I do with this game. The game devs were under no obligation to put things in nicely named files, extensions and folders and it appears they did not here.
You can manually document the files if you like -- certain formats might have fingerprints (magic stamps, certain structures, certain lengths...) that indicate what they are.
If you want something specific (the graphics, a song, the text...) then you can trace it. I am not sure what I feel about tracing on file system using games/devices -- on the one hand it is not usually quite as direct as the likes of the SNES or GBA or something but on the other once it all clicks it is somewhat nicer. That and PS1 debugging is not quite as developed as some other systems. If you want to do that for the various aspects of the game then you can build up a picture that way.
Corruption is a thing. I know it has fallen out of favour a bit around here but edit some of the files and play the game, if it crashes at a point or something loads that is far different to what it normally is then you have an idea of what it is.
I should also note some games on the PS1 and PS2 store things outside the file system. Square (Enix) were notorious for this.
If you want to check other regions for the game, if the same game is on other systems then those, or other games from the same dev then that might yield something. Or it might not.