Start-up blew my mind!
I watched Start-up while it was airing, and I am still thinking about it. It was/is one of these dramas where you just need more of it.

STORY:
The Story evolves around Seo Dal-mi, a girl from a low-income family. Her father always dreamed about having his own company, which lead to major fights at home. Her parents divorced, and her mom took her older sister with her and married another man with loads of money. Dal-mi stayed with her grandmother and father. Her father dies after a car accident, and she remains with her grandmother. Because she is a lonely girl, her grandmother makes up a pen pal named Nam Do San (based on a proper person in Korea). A boy who lives in her grandmas shop helps her with that. He is an orphan and does not know where to go.
Fast-forward to the future. The orphan boy Han Ji Pyung is very successful and own some companies and works at sandbox. Her sister is also very popular because of her step-fathers social background. Dal-mi could not go to university because of money issues and works several part-time jobs.
In Seoul, there is this fictional space "sandbox". There, start-ups get the chance to find employees, resources and connections.
Every year, Sandbox offers a competition for young entrepreneurs to find within 48 hours a team and develop an idea and pitch for a start-up. The best 4 teams will get financial support, an office and employees for free for several months. When Dal-mi meets her sister, which has everything she ever dreamed about, she tells her that she and her pen pal Nam Do San will join Sandbox. Her sister will also participate in the competition. This leads to Dal-mi searching for the real Nam Do San.
Nam Do San is one of the smartest boys in Korea, and he works with his two best friends on their own start-ups. However, they never seem to work out and want to join Sandbox, too. Through these overlapping, all the main characters meet at sandbox, and Han Ji Pyung recognizes Dal-mi. He does not want her to know about him being the pen pal and makes a deal with Nam Do San to pretend like he was her pan pal the entire time.

CAST/ACTING:
The cast was outstanding, I believed everyone that they were the character that they portrayed. Notably, Suzy stepped up her game. She was brilliant, just like everyone else. I was drawn into the story by the great execution and screen writing. In my opinion, the cinematography was amazing, too. I wanted to join their team so bad.

MUSIC:
The soundtrack was on another level, Red Velvet and Ga-ho really carried the most significant scenes, but there were also other excellent songs.

EMOTIONS:
The show made me feel some type of way. I laughed, cried and got angry. Even now, I still feel the pain of some characters. The show managed to develop the characters in a good way and explains their previous behaviour.
I really want to watch it again soon. So thanks to everyone involved in this. You did an amazing job, and I am looking forward to your future works.
Also, the turns and twists did not bother me. I liked them very much.