All Apologies is a great single from Nirvana's third album "In Utero" released in 1993. This song is in drop D tuning and has a really cool droning type effect that comes from hitting the low D string an letting it ring out while you play a single note melody on the A string. This song actually features a cello as well, but it's also arranged for guitar so you can mimic its parts from the original track. It goes into an intense and distorted power chord 8th note pattern that's easier to play than it sounds . Nirvana's music was less about technicality and more about the emotion and structure of the music, so it's more about playing with a good musical sense rather than shredding. The rhythm guitar in particular has this cool metal influenced riff where you play a palm muted open D with a sharp staccato melody on the fifth string.