finished it 2 days ago and i am already a fan of kim seon ho. he just nailed his character of Mr.Han ji pyeong. i will give the acting cast 9/10 as everyone has performed their roles very beautifully. the fictional company of sandbox, where many future's are at stake is beautifully throughout the drama. if you are not skipping in between episodes, then production team had did an awesome work. screenplay, direction, acting, story everything is bloody fabulous.
just give it a try and you will never regret it.