Imho a very average ecci-comedy (the ecci is mostly good ol fanservice)
Animation is quite good for an OVA of this age. (0)
Story is average, but interesting and surprising for an ecci (ive seen much worse ) (+)
Characters: well there are only 2 real characters and they are really shallow (well ecci XD) the other ones are just sidekicks. (-)
I really liked the comedy of this show, many different anime-genres are targeted and the relationship between Nanako & the doc is just too crazy (++)
But as far as i remember theres just one (1) mecha episode in the whole show, so dont get fooled by the genretags on the page ^^
Here are my tags: Ecci (medium), Comedy (a lot), Mystery (little), Sci-Fi (setting)
Rated 6/10 stars, i gave it one more than 5, cuz i really had fun with the comedy
(and that isnt bad, just average, to all u crazy "it was really bad so i give it 7/10" raters ^^)