Loren Leigh does it again in this wonderful, slightly spooky addition to the Diner Days series. The previous books have been light and fluffy, which I love, but with Final Boy, there was something heavier that made a bigger impact for me. Maybe it was the 'horror' aspect or the cheating trope, which I normally loathe. Whatever it was, Loren blew me away with this beautiful story.
I will say that the cheating trope isn't what I thought it would be. Reed has been seeing Lennox's friend, Indy, for a month and he's not feeling it. Neither is Indy really, since she's

head over heels for Lennox's brother, Jamie

That's not an excuse, though. Just saying it helped me get through this trope.
I should have expected it, but the character growth that both Reed and Lennox have is amazing. All of Loren's characters have that though, so I don't know why I was surprised.
In the beginning, Reed is closed off, putting on an act that he loves his life and his job, and he hates the fact that Lennox sees him and pushes him. By the end, he's accepted who he is and has forged his own path in life.
Lennox has gone through a lot in his life; outed by who he thought loved and accepted him for being a trans-man

Ash is a diiiiiiiiick

, helped his brother through ARFID/eating aversion, and put his wants and needs on the back burner. After Reed pushes him the way he's pushed Reed, he realizes that he can't put his life on hold if he wants to be happy. 
Apart from the cheating confrontation

Reed and Lennox get locked in the basement of the creepy hotel they're filming a movie at and get found by Jamie

(which is resolved quickly) there is third act drama in the fact that Lennox finds out his transphobic ex is a roommate and polo teammate of Reed's. It could have been a lot worse (slurs thrown around, Lennox pushing Reed away, etc.), but that didn't happen, which was a relief. 
All in all, I really loved Final Boy. It made me ache with sadness and longing, and burst with joy at the unabashed acceptance of Lennox by Reed. 
I received an ARC and am happily giving a review.