i could say it's heavy in terms of plot and romance. I like death spiral because it has psychological friction between the two leads which is so refreshing lol
it is one of my fav categories in danmei : unlimited flow, which combines elements of horror, survival, and puzzles, where characters are summoned to rooms to complete survival missions.
MC(uke) can come back to life if he dies (similar to regression), everything started from the beginning when he died, that only when he is in the rooms and only he can remember what has happened before.
I really love when the male lead went from big green flag to black flag due to memory glitch caused by repeated MC restarts. He has watched MC die so many times anyway, so the more rooms they pass through the more possessive he will be.
They are so dependent on each other that they can kill others or kill themselves for each other, they sacrificed for each other so much. and there is a plot twist as to why he can come back to life when he dies in the rooms.
lol hope this help.

I will never be able to forget this peak manhwa in my entire life