The characters were its biggest downfall. All the characters were insane, demented, deranged and devoid of integrity. There was no layers to their madness. You'll have to humanize them first before stripping it away. Skipping the first step would devalue their actions and take away from the watching experience. Aside from the characters, the drama was excruciatingly slow for no apparent reason other than filling the contracted runtime. Slow burners are acceptable when they serve a purpose to either immerse the viewers into its world or to seamlessly build up the tension. The drama failed to do either. The twists were overdone for the sake of it rather than adding to the narrative meaningfully. Even then, they weren't appealing nor interesting. Once the memory was restored the drama took a sharp and sudden turn for the worst going against what it tried to build up to, this includes the ending. One more thing, there was an attempt to have a play on artistic symbolism but none of which landed well. Partially because of the two aforementioned points.