Just watched the first episode... Must say that I'm enjoying it so far! Although, because of the quick pacing, one must take a few leaps and bounds with respect to character depth, I get a good, nostalgic "boy meets girl" feeling from this show. The first episode certainly placed emphasis on the focus on Rika and Yuuichi, and I hope it'll continue like that without any dilution.
I like the ending song, too, surprisingly, although at first it seemed kind of generic, but in retrospect it sets a fitting mood.
Edit: Opening song is also great. ;D
Spoiler for Episode 1 and ED animation:
Heh a fitting first episode ending with Rika and Yuuichi at Houdai Mountain with a half-moon shining down on them. Good, quick, symbolic hook for a short series.
From the ending animation... foreshadowing a tragic or happy ending? (Perhaps Rika's wish before going in for surgery?) Or just a red herring?