Entertainment: Options are available in both English and Korean. The movie choice was adequate but not huge, and the TV selection in English was very small. However, it's a good chance to watch Korean entertainment with subtitles if you want to start early on your cultural immersion. And as we have seen with Parasite's success in the current awards season, South Korean movies are definitely worth a watch. Otherwise, maybe bring a book.
The service: Prompt and very pleasant. You're provided with an eye mask and foldable slippers, which is a nice touch. However, we were asked to keep the blinds down, and the cabin was in darkness, despite it being a daytime flight. That was odd.
Food and drink: Two meals, one at the beginning and end of the flight, and snacks like noodles available on request. The meals were substantial and tasty, with beef, gravy, mashed potato, and vegetables for lunch.
The toilets: Small but clean. As good as you get in economy.
The airport experience: Incheon Airport is well organised with plenty of food and shops to wander around. It's not only the biggest in South Korea, but one of the largest and busiest airports in the world. So it's just as well their staff are organised, as you won't face too many delays getting through customs.
The bottomline: A good way to get to Seoul in a hurry, but bring a book if you're fussy about inflight entertainment.