Invoke on something like dump/*.cst. Needs regex postprocessing, as is common.

{{{#!python
#!python

import os, sys, zlib
from struct import unpack

for fname in sys.argv[1:]:
    with open(fname, "rb") as f:
        fdata = f.read()
        
        header = fdata[:8].decode("utf-8")
        if header != "CatScene":
            continue
        
        compressed_len = unpack("<I", bytes(fdata[0x08:0x0C]))[0]
        decompressed_len = unpack("<I", bytes(fdata[0x0C:0x10]))[0]
        
        decompressed = zlib.decompress(bytes(fdata[0x10:compressed_len+0x10]))
        fdata = decompressed
        
        with open(fname.replace(".cst", "")+".bin", "wb") as f2:
            f2.write(fdata)
        
        flen          = unpack("<I", bytes(fdata[0x00:0x04]))[0]
        ranges        = unpack("<I", bytes(fdata[0x04:0x08]))[0]
        ranges_bytes  = unpack("<I", bytes(fdata[0x08:0x0C]))[0]
        headerlen     = unpack("<I", bytes(fdata[0x0C:0x10]))[0]
        
        # header structure is something like
        # uint32 filelen
        # uint32 num_ranges
        # uint32 len_ranges_bytes
        # uint32 len_header_bytes (excluding these first four words)
        
        # struct[num_ranges] {uint32, uint32} // where first is length of range, second is index of range
        # uint32[entries] // indexed into by ranges
        # with this part (the two arrays together) being len_header_bytes bytes long
        
        # we don't actually need any of that for just script ripping
        
        code = fdata[headerlen+0x10:]
        
        i = 0
        while len(code[i:]) > 0:
            # guess
            oplen = code[i]
            if oplen != 1:
                print("oplen error")
                exit()
            i += 1
            
            op = code[i]
            i += 1
            if op in [0x20, 0x21, 0x30]:
                string = []
                char = code[i]
                while char != 0:
                    string += [char]
                    i += 1
                    char = code[i]
                i += 1
                string = bytes(string).decode("cp932")
                
                if op == 0x20:
                    print(string.replace("\n", "").replace("\\n",""), end="")
            elif op in [0x02]: # linefeed
                print("")
                i += 1
            elif op in [0x03]: # some other kind of linefeed (grisaia)
                print("")
                i += 1
            else:
                print(f"\n\nunknown op {op:02X} at {i+headerlen+0x10:08X} in {fname}\n")
                exit()
        print("")

}}}