I would've finished the drama first before writing a review but this drama has so many loopholes from what I've seen and everything seems so predictable.
It's so obvious with whom the female lead will end up with. The second male lead isn't given any justice and was only hurt in every episodes (he's the one who always adjust and fix the situation). The supporting leads are the ones with the most character development rather than the main lead. Both of them Do San & Dal Mi still needs a lot of improvement especially separating their personal feelings from work (that's what we call being professional).
The drama is mostly about the "love triangle" and a little bit about success & business. If I'd make a petition, I'd rather see Han Ji-pyeong's way to success. Start Up sequel with him as the main lead and how he became a part of SH Venture Capital.
SPOILERS
And isn't it too shallow to forget the plot (which is the letters) and turn it into the hands? Yes, Dal Mi did find comfort with those hands but she looked for the one who wrote it for 15 years but when she knew the truth? Still Do San.
For me, this drama isn't one of the worst & isn't one of the best this year. It has too many loopholes and it wasn't explained carefully either. Do San's character has a lot of secrets that others know but Dal Mi doesn't, jor example he talked to Alex first before the Demo, the scrunchie was given to him by Han Ji-pyeong. He was too oversensitive, emotional, and kinda manipulative.
Just give a happy ending for Ji-pyeong and In-jae. They focus on their career and business more rather than love. That's what START UP should be, business. Not some predictable love story clichè.