High Quality Content by WIKIPEDIA articles! "The Hardest Part of Letting Go... Sealed With a Kiss" is a song by the American heavy metal band Megadeth, which appears on their twelfth studio album, titled Endgame. The album was released on September 15, 2009, and the song was written by frontman Dave Mustaine and guitarist Chris Broderick. While Megadeth is a thrash metal band, "The Hardest Part of Letting Go... Sealed With a Kiss" itself is a heavy metal song, sharing a style similar to some of the songs from Cryptic Writings, Megadeth`s 7th album.