I’m sorry if anyone was looking forward to hearing a firsthand account of this event because it took me forever to write about it. However, if you still care, do read on!
My lovely friend Michelle told me about this event. It was advertised on the Visit Korea website and Facebook, and since Big Bang was advertised as the main guest, I immediately started hyperventilating at the chance to see them two weekends in a row (and for free!) and immediately entered the contest. However, because I was not one of the first 300 foreigners to email the event coordinators because I’d been in class until an hour after the concert was announced, they initially told me I had responded too late and would not receive tickets, and I was very disappointed. However, a few hours later, they emailed me (and everyone I know) back and told us that we could go, after all, because they had opened more seats for foreigners because of the high demand. Yay!
We had to collect our tickets at the Olympic Park stadium (same place Big Show was held, and every other huge concert in Korea) before 1PM on Sunday and the show ended at 8PM. Of course, Big Bang did not appear until the end. So we spent 8 hours hanging out at the stadium. (I could have gone home and come back later because I do not live very far from the stadium, but I was interested in seeing the other singers, too.) Plus we had seats and it was warm inside and there was a lot of food so it was a very quick and comfortable wait.
The concert started at 3 and opened with Tiger JK doing a song while a bunch of models walked around the runway. I thought he was amazing and I think he was actually rapping, and the way he performed while the models walked around him reminded me of the Victoria’s Secret Fashion Show. After that, two designers would showcase, one group/singer would perform, and two designers would show again, etc. As far as the fashion went, a lot of it was very interesting, albeit kind of boring, and, as I later learned, most of the designers were not even Korean. Most were European. I’m not sure why they did not showcase the products of Korean designers, unless perhaps Korean designers were in charge of creating these foreign companies’ clothes in Korea. I liked seeing all the male models.^^ Plus, several celebrities walked in the show; most famously, one of the guys from 2AM (Chan Seong? Chang Seon?)
Some photos of not great quality:

Infinite

Secret

Girls Generation
MBLAQ

Big Bang
Big Bang again (there are like 50 pictures on my camera and they are all almost identical to this so no need to share any more!)
Music-wise, here is what I thought. IU: adorable and angelic but obviously lip-synching. Crazy male fans shouting chants throughout all her songs. T-Ara- the worst lip-synchers of all. Moving their mouths when there were no words, or moving their mouths out of time to the music. Their dancing did not look so hot, either. Maybe they were having an off day. They are Korean idols, after all, so they probably do not get to sleep or eat very often. Secret- I like their songs but they were kind of boring to watch. Miss A- good dancers (and they did their leg dance!) but also not very exciting. Infinite- boring songs and boring dances. They all looked really, really young. MBLAQ- a more exciting performance. I have always wanted to like them but I just can’t get into their music. They danced really well. However there was some problem… it looked like one of them was bleeding on his face. Later on, one of them ran offstage (I think) and a dancer dressed like a ninja replaced him for the rest of the set. That’s what it looked like to us from afar, anyway. Girls Generation- only 7 performed. This was my first time seeing them and they were not particularly amazing. Mighty Mouth- They were a surprise guest and I thought they were awesome! I like their music a lot and they really got everyone excited.
Finally, the highlight of the show came on- Big Bang! They sang Blue, Bad Boy, and Fantastic Baby, and really brought down the house. They were really into it, singing and dancing perfectly on point, and driving everyone in the audience crazy. Plus, there was a ton of confetti swirling around them and it looked really awesome and epic. At some point they all went around and introduced themselves, and we all cheered for them individually. Daesung got the loudest cheers.^^ Unfortunately, their performance was over almost as soon as it had begun.
I am not sure if this information has been released yet, but I am 100% sure that a televised version of this event will be held on Korean TV. Probably MNet. There were two hosts talking throughout the show on a podium to the side, and there were a ton of cameras filming everything; the stage and the people. A camera guy walked right up to my face and stuck his camera in front of it for a good 20 seconds (which felt like 20 years, while I tried to awkwardly pretend I didn’t see it) so I will have to watch it on TV to see if I made the final cut! Haha.
This is about all I can think to say about the concert, but if you have any more questions or want to know more details, feel free to message!