So, I kept away seeing this series thinking it might be overhyped and because reviews kind of told this drama is traumatic. But I am glad, I decided to watch the trailer and give it a chance. And all it took was the trailer to convince me watch 2125.
And if you are reading this review with a dilemma to watch this series or not, trust me, and watch the series right away. (And come back later to this review so that you feel connected.)

I felt a lot of emotions while watching this series, be it inspiration, the will to work hard, motivation, happiness, pain and love.
There's nothing I can point out as a flaw in this drama. The story, the way it is told through this series, the actors and the acting, the ost, the emotions it conveyed, I couldn't ask anything better than this.
So what I liked about this series :
~ Both the main characters, Na Hee Do and Back Yi Jin
Tbh, Hee Do inspired me to live life and work hard no matter what, the sparkle in her eyes conveyed hw she dared to hope (the way she tells in the last episode .
I could relate to both the characters personally and feel every emotion the went through.
Yi Jin, I couldn't take my eyes off his eyes, his eyes conveyed a million emotions. The way he gracefully accepted his hardship and navigated through adulthood, the way he tried to manage both his personal and professional life, the way he could see the happier things of life (through Hee Do), as a teenager I hope I will be a little of him in this aspect.
~ the friendship and fencing
The other main characters, Ko Yu Rim, Moon Ji Woong, Ji Sweung Wan, the way rivalry turned into friendship and and how a girl and a boy can be just friends and how strong and supporting love can be (in case of Yu Rim and Ji Woong )
~The realistic portrayal of a mother-daughter relationship
~ the mature take on love ( You Jin and Hee Do)

I learnt so much watching this series and got to see a different dimension of youth and 2125 taught me to see my life in a brighter shade. I looked forward to see each episode, 2125 made me reflect on my own self. And about the ending, I personally believe that all love stories don't get a happy ending. So I believe the ending was realised ad just perfect.
My favourite dialogues were :
" I don't regret meeting you or loving you. Wanting to falter and letting myself falter is my mistake. A mistake that is clearly not minor."
"Life is long and fireworks are short."
" I don't think not living your dream means you have failed at life. And I don't think living your dream means you have succeeded either."
"It isn't a rainbow, it's love."
"My result was amazing and the process was beautiful."
My favourite ost is Very slowly and Go! (I am hooked on them).
I will definitely re-watch 2125 because I went through a lot of emotions while watching and I will definitely love to go through these emotions again.