While Bastion is one of my favorite games of all time, I wouldn't say that it's because of the gameplay. If you were to isolate the gameplay from the rest of the art, you're left with a somewhat mediocre game. Logan Cunningham's narration and Darren Korb's musical score didn't just carry Bastion, they sprinted away with it.
The video that I've provided is my favorite example of Darren Korb's musical and lyrical prowess. The first song is "Build That Wall," a folksy piece sung by the character "Zia." The second is "Mother, I'm Here," a lonely tune by the character "Zulf," which is utilized powerfully in the game's third act. The third is a mash-up of the two, played during the game's credits.
I wasn't particularly attached to either of these characters, but these songs did make me cry--a moment I owe entirely to Darren Korb.