The first half pre time skip was a lot of fun but then it got serious and sucked out all the fun out of it. The relationships in the second half weren't good enough to compensate that. A lot of pointless push and pull that always led to a dead end until they reach the last scene of episode 16 to change that. Kwon Sang Woo did a fantastic job, he was the perfect embodiment of his "trust me bro" character. Unfortunately, again, they tuned down his character in the second half. The same thing can be said about how chaotic Chae Rim was in the 1st half.