@chrispower110
The manga changes very, very little (I've given up on calling it a manhwa lol. Feels bad)
Anyway, the biggest changes are that the manga adaptor sometimes skips smaller scenes or unimportant dialogue. Or changes the nuance through his art (like making a character look angry instead of surprised, things like that.)
So nothing important is skipped or changed.
In volume 3, there's an entire scene where Rangii and Sunghoon do some kind of ice bucket challenge (it's a Korean cultural/Internet thing, not a reference to the ALS ice bucket challenge) but it's skipped in the manga. For good reason. The scene is ultimately worthless and doesn't add anything to the story.
The adaptation is quality work, with the only real problem being pacing b/c the author likes to continue strings of dialogue that are easy to read quickly in text, but much harder to read quickly in weekly chapters of manga.
@Oslight You're welcome! Thanks for reading XD