As the name suggests, its a song about not only friendship surviving the test of time, but a nice trip down the different music from day's past. From classical twilight
Fluttershy referencing "The Sound of Music"
Rarity on LSD, or "Sgt. Pepper's Lonely Hearts Club Band".
Rainbow Dash tapping into her inner Joan Jett
Applejack and country.
And it ends with Pinkie Pie and New Wave.
There was tons of music references that was not cancer, including one of the best bands in music History: Queen.
Life is a Runway
There's a reason Rarity is called "fashion horse", it what she sleeps, what she breathes, what she eats, and what she shits: fashion and fashion accessories. This song nailed that well-known quirk of hers in the head, with Rarity not shy about getting flirty.
Or doing that
Or... looking like that
The song by itself felt like it could have been a hit single by Madonna, because of a "Vogue" like feel to it.
If the topic of fashion, or making yourself pretty isn't your thing, there is the animation, which compared to the first movie has really improved.
But seriously though: How cute was Rarity's smile at the end of the song
My Past is not Today
First off, Sunset's wardrobe change is too cute, and the only EQG design that isn't ruined by those damned knee high boots.
The song is well sung, has a deep message about not letting one's path defy you, which would be a good message overall. also sunset "mai waifu" shimmer, because why the fuck not.
Again, the animators have gotten better at the >no hooves game, and if it is any indication of season 5: it will be better animated than (insert any cartoon network show here)
One thing that was wanky was the running animation, the animators still have a lot more tinkering and trial and error to get it down.
Overall, if the hype train was not on full speed ahead, it sure as shit is now.