Location: Jamsil Station, exit 3 and follow the signs; it is straight to the corner, turn right and it will be on your right.
Venue: The place is beautiful on the outside, reminiscent of an old opera house perhaps or as Visit Korea says, "it imitates the elegant ambiance of Europe's high-class architecture design". The inside is just as lovely, with the same classic design and decor. The whole thing looks out of place in it's location near Lotte World, but in a happy accident kind of way.
Experience: Once inside the theater, you are immersed in the world of the show. Sitting in the back, you still feel almost in the musical. However, sitting in the front, you are in the musical. At intermission, they have ice-cream and light refreshments for sale. There are plenty of doors, so that exiting or entering isn't congested. They sell musical memorabilia and have picture places up, like a life size cutout of the cast. The bathrooms are big and well-kept. Overall, the beauty and layout of the theater make up for the shortfalls of the staff.
Staff: Arrived about five minutes late, which I thought might be a problem, but it wasn't mentioned on the ticketing site. The first floor staff greeted us kindly and sent us up stairs, stating that we would be seated in five minutes. The second floor staff greeted us and said we would be seated in ten minutes. Then they said we would have to sit in the back and not in out seats since we were late. I complained that they didn't tell us this originally and they said oh well it is so dark that you can get hurt going to your seat. They kept changing their story/excuse as to why we couldn't sit in our own seats: too dangerous, might disturb the audience, isn't fair to others who came late and had to sit in the back. I even asked well, what if I was sitting inside already and had to go to the bathroom, could I exit the theater, go to the bathroom and return to my seat? The answer was an emphatic yes, but obviously my situation was different. They were quite snippy overall and at one point they even said well you can't be seated at all then until intermission because you wasted too much of my time.
Anyway, while I understand the seating arrangement, my problem was actually that they lied and changed their stories as on a whim. If you have a rule, simply say I'm sorry, but we have a rule that if you come late, then you must sit in the back until intermission. Don't lie and don't quibble, it makes your establishment look bad.