It took a year to make this picture...
...because the producer was financing it with bonds and CDs. He could only film parts of it each month, then wait for the next bond or CD to come due the following month. Alright, I'm just guessing, but I'll bet that's what took so long.
PS Those are the most hilarious monsters I ever saw in a movie. They make Ghimera, etc., look like they were built by DaVinci.