This is a Psychedelic song by a Psychedelic band. But actually they didn't really care for the song, played it rarely in concert, kept it short, and in fact left the Psychedelic behind just a few short years later, becoming Progressive giants.
Originally, the song was much longer but when cut down to single length, they lost a lot of recorded material. There is a keyboard part after the first chorus that sounds like no instrument I know. Research says that it was a piano, played much slower, that was sped up to fit into that part of the song. There's a lot of psychedelic organ going on after the second chorus courtesy of Richard Wright, plus some just crazy sounding guitar licks from Syd. Just as that ends, the bass tag, before the third verse starts I would swear that's a tuba playing along with the bass, but there is no tuba listed. It's the same bass tag you hear going into each of the verses. I just think it's easiest to hear on the last one. If it's not a tuba, it's one hell of an organ.
The original 4 track master recording is lost and there was very little paperwork done for the song. The engineer and producer both recall using lots of backward taping, reverb, and echo. The echo effect is clear on the backing vocals on the chorus.
It's a very brief pop song, without it, Pink Floyd never would have soared to such popularity, which in turn might have kept Syd sane longer. But then the band wouldn't have hired Gilmour, and then we wouldn't have the classic albums of the 70s. BTW, Bowie's cover is pretty odd as well. Very easy to imagine it performed by the Goblin King Bowie, backed by Henson goblins.