There were some interesting concepts and good characters here, but at the end of the day, Memai fails to deliver satisfactorily on either . I feel that Tanaka Suzuki's the kind of author who simply can't write oneshots, because all but the fourth chapter in this collection felt more like the prologues or epilogues of much longer stories.
Memai -- The premise wasn't bad per se, but the two main characters' actions and thought processes were pretty baffling, to say the least. Perhaps if a few more chapters had been spent on exploring their lives and personalities I'd have understood and sympathised more. 3.5/10
Slow Starter -- Typical romance/BL plotline. Unoriginal, with dull characters and very awkward development both character-wise and relationship-wise. 2.0/10
Teikuu no Akaitsuki -- Felt like the 1st chapter of a ~10-volume series, and therefore grossly inadequate as a oneshot. 2.5/10
Hitokui -- The only story in the collection that I didn't regret spending my time on. For its length, it was a fairly entertaining exploration of twisted love both familial and romantic. 7.0/10
Campus -- Would have worked better as your typical single-volume BL school-life comedy, but a failure as a oneshot: the premise had only barely been established before the story abruptly ended. 2.5/10
Tl; dr -- Just read the fourth story. [But note that it's a (tragic/unrequited) het romance, with not a hint of BL in sight]