I personally found the drama quite enjoyable at the first half. I agree with the majority that the plot's direction shifted in the second half, but I also believe it wasn't entirely unexpected. The change occurred because the characters themselves evolved; they transitioned from being adolescents to young adults, making their own decisions and facing the consequences. Additionally, we gained insights into the male lead's past and saw the female lead overcoming certain challenges to pave her own path in life.

Therefore, I'd describe the first half as focusing on two youngsters with troubled backgrounds who find solace and support in each other meanwhile in the second half, they are young adults who reconnect and develop deep feelings for each other while pursuing their dreams.

The drama isn't the best, but it's not the worst either.

P.S. : I'd recommend watching the special episode to find more answers.