The main trick is that once you survive the movies, you gain points which you can use to upgrade your body and mind. Think of stuff like vampire bloodline, Qi, magic, mental powers.
Resident Evil, Alien, The Grudge, The Mummy, Final Destination, Jurassic Park
The MC says something along the lines of "I'm going to die" or a version thereof at the end of almost every chapter his perspective is shown. (or he says something else 'negative')
One of the presumed running gags is him wetting himself a little at occasion, which the 'beastmen' perceive as marking his territory. Making them think he's strong instead, rather than afraid.
It seems like the white/grey light will also show up during other types of performances, such as dancing. It helps KangYoon judge whether a performance is good or not. This helps during recording, dance practice etc. And it helps him show the part where it goes wrong, cause it turns grey then assisting him in noticing what to do or say.
KangYoon's ability further 'evolves' later on during the novel. He can see more types of lights and other difference makers that weren't initially shown.
Have faith in the Lord Fifth, gain eternal life! When the Lord Fifth appears, who dares to cause strife!
The MC once found some ancient chants, which strengthened his soul and is the whole reason he's able to reincarnate and have his former memories. Except apparently the chants also somehow inflict him with the inability to produce off-spring (he can't have kids). I somehow find that addition to be somewhat ludicrous and I don't understand how his soul would make him infertile, when that should be purely a bodily function. I personally enjoy it when a MC at one point can have children. To cut that path off at the very start is a minus to me.
It felt like the author didn’t know what to do when the MC was in a sect... so he decides to kill off the sect, just to make the MC wander around again and give another motive for revenge.