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.
Cliché Storm: SETH's speech. Day of Reckoning is filled with this, as well.
Complete Monster: Andrew Scott from the first movie was a sergeant in The Vietnam War, where he goes renegade as he starts butchering civilians and kills his own squad when they try to stop him. He cuts off the ears of his victims and wears them in a necklace. He orders Private Luc Deveraux to kill the two remaining "traitors," two Vietnamese children, doing the job himself when Deveraux refuses. Both are reborn years later as memory-wiped Super Soldiers. As soon as Scott regains his memories he kills his controllers and goes on a blood-filled vendetta across the States to punish Deveraux for disobeying his illegal orders back in Vietnam, graphically killing anyone who gets in his way. At the end he takes Deveraux's elderly parents and his love interest hostage, awarding all of them the death penalty. Despite claims earlier in the film that he thinks he's still fighting the insurgents in Vietnam, Scott later plainly admits that he's fully aware where he is and what he's doing, and his only motive is revenge for Deveraux refusing to partake in his atrocities.
One-Scene Wonder: Lundgren in Regeneration and Day of Reckoning. Also Van Damme in Day of Reckoning.
Paranoia Fuel: Day of Reckoning is full of this. You could be a cloned genetically-enhanced sleeper agent, living a typical life until suddenly you got sick and hears voices that briefs you on your new mission. After you completed said mission, you know nothing about it because your memories were tampered with again.
Special Effect Failure: The Return has some painfully obvious CGI effects, for a $40 million budgeted movie. Especially jarring when you consider that the rest of the series have much more impressive effects despite being no more expensive than $20 million, or heck, $11 million.
What an Idiot: SETH kills Cotner, who, along with Deveraux, knows a computer code, which SETH needs to avoid permanent memory erasion. Not that it stops him from becoming a UniSol, let alone cracking the code by himself...