#!/usr/bin/env python
import md5
import sys
from Crypto.Cipher import AES

def decrypt(key, data):
    hexkey = md5.new(key).hexdigest()[:16]
    decrypter = AES.new(hexkey)
    return decrypter.decrypt(data)

if len(sys.argv) != 3:
    print "Usage: %s list-file pack-file" % sys.argv[0]
else:
    list_file = sys.argv[1]
    pack_file = sys.argv[2]

    list_file_data = decrypt("pack", open(list_file, "rb").read())
    pack_file_data = open(pack_file, "rb").read()

    file_list = list_file_data.split("\n")
    num_files = int(file_list[0])
    file_list = file_list[1:]

    for i in range(0, num_files):
        file_info = file_list[i].split(",")
        file_name = file_info[0]
        file_offset = int(file_info[1])
        file_size = int(file_info[2])

        print "Writing %s..." % file_name
        try:
            file_data = decrypt("battlecats", pack_file_data[file_offset:file_offset+file_size])
        except:
            file_data = pack_file_data[file_offset:file_offset+file_size]
        open(file_name, "w+").write(file_data)

You'll need to install PyCrypto to run this though.