Well, for me it was slow as well. But the way the 5 parallel plots run in the second season and its relation to the first, kept me interested. The judiciary vs Police with corruption added, The secret behind Hanjo Global Corporation, The dead Lawyer in the middle of a highway, A disappeared Public Prosecutor and the drowned kids. The leads are in the middle of all this. In the end, the puzzle is complete and we get all the answers. Its more like little pieces of a jigsaw put together in the last 2 episodes.
Pro Tip - Fast forward the dull and boring bits