If you like short series and BLs it's worth watching.
About R rating... We have suicied thoughts in 7 episode!

First of all story is really interesting and you might really easly get hooked. At some points is not great delivered and some scenes might look rushed, but reason is known, it's just to short to explain everything.
Second thing is acting. Chemistry beetwen Hyunjun and Yoojun at begining it looks little bit akward but I don't think is but thing (ofc as we see it from Yeonwoo's point of view, cuz Yoohan is to up front) Yoojun is really great actor. I can see suffer on his face and I like his eyes express emotions. For Hyunjun... I liked his acting but I don't know what to think it about in last 2 episodes...
Music is beatiful! And production is great even it had low budget. Color rush at begining might be for the first time really funny.
I personally adore whole series. I definitly gonna reawatch show.
This bl have happy ending so don't worry! And lots things are explained in last episode.