Plot-wise, the first one shot was well executed, the twist was nice - although you could totally see it coming ( I guess the satisfaction comes from you confirming it?) while the idea of an everlasting live may seem romantic, It doesn't really seem realistic and may actually be downright sad and depressing.
The guy devoted his entire youth to his girlfriend, I wouldn't be able to do that...
Flaws aside, this one shot is a pretty good read, the art is clean and the ending, a happy one. While I might have been harsh on this one-shot, I liked it and still reread it from time to time.
The second one had a lot of potential, but my oh my did it veer off course... I almost flipped my desk in anger when I finished it. The concept of reincarnation is pretty neat and is one of my favourite themes to look for in manga series, but that still didn't save the one-shot for me. The whole story actually felt kind of "forced" like a commentator earlier had mentioned - like it had to end "that" way. It might have been because the one-shots were published in Betsucomi and editors encourage mangakas to write about hetero couples, but in my opinion, it might have been better if Yasuko-sensei left the two protagonists as is.
The third one was pretty average, it was cliche but was still fun to read and I guess the female MC was likable to a certain degree. I didn't have any high expectations reading it so it was alright.
Overall, this collection was decent, I'd recommend people read the first story and decide whether they'd want to continue on from there,