Starts out really strong, but the last part doesn't really add much with a weak conclusion. Translation goes to shit as well at some point.
Might give the anime a shot for a different angle.
It's a short read, but it's also not worth that time investment. Potentially interesting plot elements go nowhere, and the final chapters are a standard 1v1 action manga final boss fight. It was very promising early on and then just fell apart.
Empathy, compassion, kindness... are fundamental parts of what makes us humans, and it was a recurring theme throughout the manga. So It can't end better than Shinji, after defeating the parasyte as a human, having doubts about killing him or not, but making the most level-headed decision in the end. And the killer in the last chapter was to tie up loose ends and emphasize that not everyone has natural empathy, I guess.