It's not good, but it has a enough ridiculous moments to make it worth a poke. The chimp throwing the grenade is classic. Also, there is a surprising amount of nudity for a PG movie. Like, it must have just missed the creation of the PG-13 rating, but then I can't think of any PG-13 movies with this amount of nudity. This would definitely get a R rating now, which seems absurd to write, but it would.
Things I would do differently.
1. Remove the food from the freezer where they put the bodies.
2. Build the wall out of something stronger than cardboard.
3. Close and seriously board up the doors behind the built wall.
4. Seduce Francine away from Flyboy.
5. Take all the guns out of the gun store.
6. Never take off the fur coat.
7. Eat a whole ton of cheese.