Hypnotic and Chilling
Musically, the release is just as awesome, pulling a powerful drama out of a light backing track and smooth, soft vocals. It's spatialized well and there's just enough of an undertow provided by the repetitive trills of the low synth / piano line to give the track an urgency that plays well off the plaintive vocals. It moves well and evolves nicely and it's over-all a great track.
The styling's great, and the choreo's fun, though I wouldn't call it revolutionary (it still suits the video and the track perfectly well). The only thing I would consider changing is the very end when Donghae sees Eunhyuk walk out of his last session with no memories of his past relationship. I think it would have been interesting for him to see that and decide not to forget, just to make it a bit more interesting (like have him look at the erasure card in his hand and then dropping it and walking away rather than heading in for his own session). I like how it currently ends though, so it's not a deal breaker, but I do think it would make an interesting statement.