I remember this film from my younger days- probably saw it in black and white! To be honest, i do not think sfx are essential to a good film: from the Iliad onwards, a good story and storytelling remain the essential components and sfx is just a cherry on the cake. The trouble with modern films is that the sfx budget has taken over- to the detriment of the story, which is too often shallow, superficial and poorly told.
The fact the aliens look a bit silly is neither here nor there (imagination does far more). What one has a to question is a plot which features supposedly intelligent aliens- they manage to cross a great distance of space-with an aversion to water, who invade a Scottish island!!!! Duh! Why didn't they do their homework first? Invade the sahara, or somewhere suitably dry? I can imagine quite an enquiry back on alien homeworld....
The fact the aliens look a bit silly is neither here nor there (imagination does far more). What one has a to question is a plot which features supposedly intelligent aliens- they manage to cross a great distance of space-with an aversion to water, who invade a Scottish island!!!! Duh! Why didn't they do their homework first? Invade the sahara, or somewhere suitably dry? I can imagine quite an enquiry back on alien homeworld....