Imagine had the Walt Disney SFX department handled this
I like this film a lot and find it one of Hammer's very best, but the inconsistency behind the special effects is the major flaw. I know their budget was limited, but that didn't stop them from scaling their earlier scripts down to fit budget limitations.
Since the "knight of death" sequence had optical effects that reminded me of the banshees of Darby O'Gill and the Little People (1959), I wondered how cool it would have been had Hammer collaborated with some of the special effects artists of the Walt Disney live action SFX department. Forbidden Planet did that for the sequences that showed the alien, for example.