Might be reflective of the national cultural Zeitgeist.
For instance, China’s is rather appealing, stressing duty, honor, courage, national defense:
Chinese People's Liberation Army recruitment video. What strikes me most is the totally different ethos than the ones present in US military recruitment video that we are all familiar with. pic.twitter.com/WKqYUOkyCJ
— Carl Zha (@CarlZha) October 19, 2018
The US video features some random pointless adventure in the Middle East:
— U.S. Army (@USArmy) October 18, 2018
Here is a classic Russian military recruitment video, released in May 2014:
Translation: “This is … the first day of your new life. … That’s the new slogan the Russian military is using to attract recruits, according to what appears to be a new video for the Russian armed forces. The video, which first appeared online in early May, shows a young recruit thinking back to his time kicking a soccer ball around his neighborhood, hanging out with friends and lying in a wheat field with his lady. … Who you were yesterday doesn’t concern anyone anymore. What do you know about yourself? What are you capable of?” the voice-over says in Russian, according to a translation. “The questions may remain without answers, but would you be able to sleep well? … To know yourself is to know the limits of your abilities. To hell with limitations! Are you ready to break yourself, every day? Here pain makes you stronger, scars are a daily occurrence. Here you decide to prove something to yourself. … This you try to see in each shadow of your enemy, because without an enemy there is no battle, and without a battle there is no victory. But in reality, the main enemy … is you, the you from yesterday. Your mission: Track down the enemy, catch up with him, overcome, become better than him and return as a victor. Because tomorrow is the first day of your new life.”
In fairness, that video – which included the phrase “to hell with limitations,” but could also be translated as “to hell with borders”, rather appropriately given contemporaneous events in the Ukraine – wasn’t entirely typical.
Here is a more recent, less aggressive one.
Japan’s videos seem to be played by J-Pop sidekicks:
In fairness, that video was probably extreme, even by Japanese standards. I assume that this more recent video, also popsy but less overtly gay, is more typical.