picked this up cheap, as I've managed to watch the first 3 Ghoulies movies (thought 1+3 were boring, 2 is ok in a crappy kinda way).
but this one is something else. it's like the director wanted to make a sexy, wise-cracking comedy/thriller cop movie with supernatural overtones (like you do), and then at the last minute was told by the producer that it had to be a Ghoulies sequel, so he got 2 guys in monster outfits to run around for no reason, then inserted their bits into the rest of the movie at random. the 'ghoulies' have about 1 minute of screen time that is irrelevant to the rest of the movie!
worth a watch if you're bored. some of the dialogue is Samurai Cop-esque (nice convo starting at 54:45.. "quit calling me hun, hun!")