Reading the summary of the movie I thought this was a sci-fi / dystopia movie, but watching it I realised halfway that this is in fact an adventure espionage thriller like the James Bond movies, although without the gadgets and with a teenage boy (it's a Czechoslovak movie alright) instead of an assortment of hot women being the contact of the spy who infiltrates the base of the evil genius.
The setting is a late 19th / early 20th century alternate reality, and the army in the evil tyrant's city looks like German soldiers in WWI. There are also no advanced technologies. Messages are exchanged by mail pigeons, and people use horse carriages for transport. There is a single automobile in the movie, which is so unusual that a guy must be running ahead of it all the time to warn people to make way for it on the road. So this is clearly not science-fiction in the current sense, although it was obviously written as story from the not too distant future by Jules Verne. The only real element of science fiction in this story from his vantage point was the idea of a weapon of mass destruction, more specifically a chemical weapon, which the story is essentially about, but these have also been unfortunately very real for the past 100 years.
The utopia / dystopia theme is not really explored in the movie at all (I don't know if this is different in the original literary work). The opposing states in the movie are basically no more than a peaceful, wealthy democratic city state and one that is an impoverished militaristic dictatorship that oppresses its citizens and is obsessed with industry. Now since the latter is, and was also for someone living in the Eastern Bloc, quintessentially recognisable as the Soviet Union, I really doubt that this movie was really meant as a propaganda effort directed at the United States, or if it was, it surely didn't work well as such at all. So this should be watched as an adventure movie rather than science-fiction.
The acting is very convincing and the story exciting. The tone of the movie is serious as it deals with a weapon of mass destruction. In spite of the young boy playing an important role this clearly isn't meant to be children's movie, although it should be perfectly safe and exciting to watch for children above, say, age 10. I'm sure I would have liked it at that age.
There are hardly any special effects, but given the topic none were really necessary either. The only really weak part of the movie for me was the fight between the main character and an important bad guy. The two men wrestle and punch each other, but this is quite poorly choreographed. What is much more irritating though is the fact that during this fight the little boy manages to disarm the bad guy three times while the main character, a grown man, just keeps getting beaten up (and almost shot) by him.
