Yeah it's plot went smoothly on season 1 and half of season 2. Until a little turtle suddenly become a big hero, haha

Not clearly where is it from, and suddenly its a hero that solve big things. Then why kim dong ju can't go out from jinyowon cave? Why every great magicians suddenly become villains and don't matter to ruin the world?
Why su yon where jinmu switch the body just startled and not even try to move or run?
The fight with dwajo (fire bird) also done poorly.
Etc.

The 2-3 last episodes like a mess and joke + ruined everything. No logic at all. It could have been better easily with just a few tweaks and explanations.

Anyway since half of it still good and we have to have s2 for their happy ending, I still give 7/10 for this.