Some of their later music is somewhat weird. But these guys were popular when I lived in Korea. One of the legendary kpop groups (others being SES, Shinhwa, Finkl, and i think I'm missing one...)
Song starts like half way through the video.
G.O.D.: 길(pronounced: gil) [Trans: Road]
Oh by the way, if you haven't started the vid yet, the guy on the left played Yamcha in Dragonball Live Action Movie
"어머님께" [Trans: To mother] & "촛불하나" [Trans: One candle]
Note: when these guys were around, there were no such thing as HD vids I'm sorry