must say left feeling flat - the acting was good, but the plot wasn't my cup of tea (& not talking about the same sex attraction issue) i don't come from a devote back ground, so seeing someone this addicted to religion is foreign to me.
& yet get that as Yoo Han was all alone / an orphaned, he turned to god for comfort, as he turned to the church & the community it gave him, to be a substituent for the family he didn't have.

Joo Won to me was the embodiment of the serpent in the garden of Eden, u never got who he was or what his ulterior motive was - u just got that there indeed was one (not to mention he was shady as f*ck IMHO). he was quick to pick-up on how he effected Yoo Han. he kept getting close to him without actually crossing any boundaries, cause he suspected Yoo Han would run for the hills the sec he did.
but he kept finding ways to be in his vicinity (tempting him), kissing that girl - maybe she was another soul he needed to corrupt - one that took a bite of the apple. same as Yoo Han eventually did. also the reason he disappeared afterwards without a word - his job was done

also the reason i thought of this was cause of the girl in the prayer meet & her weird / scary dream of a serpent swallowing Yoo Han whole - considering what happened it indeed did....

the reason am left "flat" after watching, is cause this was depressing to me, Yoo Han's brainwashed attitude with religion - his lack of life & being open & vulnerable to bad people leaves me feeling depressed. so well acted but a one off