Gelin Halayi is the ultimate wedding party song. There's a specific dance "halay" and you do the dance in occasions like a marriage. So gelin halayi means "the bride's dance/halay.
DIV DIV is more of a love song. telling how sweeter than honey his lover is etc.
Akyol says. “I’m looking inside my consciousness to my culture. I love rock but there are hidden things in my subconscious. Call it Turkish art rock if you like.” Altin Gün