PS - I didn't know it was Miyazaki's debut film before watching, but looking back, I can definitely see his style.
The country, the architecture, the castle are all just so beautifully drawn. The fight scenes are incredibly fluid and energetic. It was made in 1979 and so, there are a couple of tropes that haven't aged well - specially the Damsel in Distress, but other than that, the plot is solid. The female characters, when they're present, aren't overly sexualized. It's just a very well made film. Above all, it's just so fun! The chase scenes are freaking hilarious. The villain is plain evil so you don't have to think about any morally gray areas or whatever. Just sit back, relax, laugh and have a good time.
Highly recommended.
Weirdly I've always interpreted him and Ghibli as a whole as being perceived as "above anime", like Anime is sometimes viewed as a niche or lesser form of art/broad genre while Ghibli is sorta viewed as transcending those barriers.