While watching Start up I read some reviews on various sites about the show that disappointed me. So here's my opinion.
Start up was a really nice drama. The whole start-up company theme was always interesting to watch and sometimes it was so thrilling to watch how and if Dal Mi, Do San and the others would face the challenges in their way.
The thing that disappointed me in some reviews, as said earlier, is that some people who liked the second male lead would attack the main actor and they would make some questionable statements about the storyline, e.g. there was a comment where it said that only the actions of Ji Pyeong were the writer's doing and not all of the other characters. Surely I wasn't always agreeing with how the main leads were acting but it's a drama you can't expect that the writer has the same opinions as you, something that happens with all dramas.
Acting was good and the chemistry was there. Loved Sa ha's and Cheol San's relationship, cuteness overload really. The music was lovely and it's one of the dramas I would go back to watch.