[NO SPOILERS]
I didn't read the description, so going into this, I didn't know what to expect. I had heard on Twitter that the HIStory 1 series was basic and simpler than the others, so I was prepared for a fluffy romance.
For the most part, we got that. The beginning was really confusing, I didn't quite understand what was going on and, on episode 2, had to rewatch the first 10 minutes of the series to better understand who the characters were. Although we didn't get a clear understanding until the very end of the show, I made some sense of it and was able to continue with little problem. Once the show established everything, the pacing was really good. I can't complain at all.

If you are looking for a pure homosexual BL, I wouldn't recommend this. Despite the 2 main leads being male, one of the characters is a female in a male body, so the element of BL is lost slightly. But, it is still a quick, fun watch.

As you can imagine with there being an FTM body swap, there is a bit of toilet humour. I did find it funny but I also found it a bit uncomfortable to watch. As a female, I've always been uncomfortable with urinal scenes, and BL has so many of them unnecessarily, but that's what you get for watching a male-focused drama.

[SPOILERS]
I found the ending 50/50 satisfying. I was really hoping during the last quarter of the show that Lan Xi would realise that Hero doesn't love her anymore and that staying in Gu Si Ren's body will just upset both of them. So I'm glad that she selflessly let Gu Si Ren return to his body and accepted that she is dead. In that sense, it had a satisfying ending. But there was a straight kiss that was longer than the gay kiss, so I was pretty annoyed about that...