These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
One-Scene Wonder - Fess Parker as the pilot-witness; landed him his role as Davey Crockett.
Special Effects Failure - Compared to today's slick CGI, the ants look dated, but the giant models were impressive for their time, albeit slow-moving. One reason most of the following giant-thing movies were so bad is that pretty much all of them used clumsy super-imposed images to serve as the monster.
Nothing Is Scarier - Much of the beginning of the film shows only the aftermath of the ants' attacks. We see only the damage they have caused and a few bodies, one of which is filled with acid and chewed to bits. This helped build up their menace prior to them turning up on screen.