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.
There's also the agent 'recruitment' process, which involves finding a random innocent civilian with the appropriate physique, kidnapping them, implanting a mind-control chip in their brain to suppress their free will, then strapping them into the aforementioned device to receive modifications.
Chip extraction in the 2012 game. This is done with a specialized tool which consists of a handle with a spike at the end which you jab into a person's ear or nostril, whereupon thin cables extend from the spike, dig into the brain and tear the chip out. The game gives you a lovely X-ray view of the head so you can better appreciate what is happening.
The expansion pack, despite using the same map structure in the original game, is much harder than the original. You pratically need to memorize the map and in-mission events before you can even attempt to complete the level.
Even more surprising is the very first thing that happens in the sequel, Syndicate Wars. Your one agent starts on a long exposed dock, and is immediately shot in the face with the most powerful weapon from the original game.