Of the 3 guitar charts from Nirvana's 'Bleach', this is probably the most difficult, and its probably the hardest of all of Nirvana's songs.
The main riff that is played often throughout the song is a tricky riff that revolves around holding Green alot and quickly hitting single-notes and HO/POs on higher areas of the fretboard, which makes it hard to keep a streak.
Other sections include mostly chords, 2-note and 3-note, but the main riff is what is played most often in the song, and that alone, is one of the things that make this chart so difficult.
The solo is seemingly random, it jumps all over the place in no particular pattern, plenty of HO/POs, single-notes, chords, time changes, all that. Its difficult, especially if you're trying to get perfect (or near perfect), but not impossible, and its alot of fun.
Overall, this chart is definitely one of the hardest of all of Nirvana's guitar charts, and even so, its pretty entertaining. Recommended if you're looking for a tricky guitar chart and like the song.