The sung melody in Killer Queen is typical of a pop/rock song. It is often stepwise which helps keep the sung melody catchy. Occasional leaps are used that lend the words a more enhanced sense of expression.

For example, the ascending melodic interval of a major 6th in bars 10-11 (0'18, notated below) on the word "decline" sounds quite striking and allows the word to stand out clearly. This is an appoggiatura because the G doesn't match the prevailing chord and it resolves when it falls down a step to the F.

There is a notable melodic pattern used in the song that descends in a stepwise manner (0'22, bars 11-12, notated below) spanning a 5th in pitch. It is often repeated in sequence which makes it stand out. It is also infectiously catchy!

The electric guitar plays lots of interjecting phrases and this sometimes includes pitch bends which are very stylistic of the electric guitar in rock music. A good example is bar 30 (0'59, notated below). There are also many slides used such as in the instrumental from 0'44 (bars 23-24, notated below) where the guitar slides from a note below to make the melody it is playing sound more intense and soulful.

A final melodic point is the chromatically descending guitar melody from bar 7 (from 0'12) which sounds very satisfying.

Africa is a rock anthem released by the band, Toto in 1982 (8 years after Killer Queen). Overall it sounds very different and relies very heavily on synths in the accompaniment (something Queen were proud of not doing for a number of albums).

The sung melody is also typically stepwise with occasional leaps, much like Killer Queen. Listen to the opening melody of the song, notated below (0'31). Apart from the ascending 3rd on the word "conversation" everything in the phrase is entirely stepwise, keeping the melody tuneful and also very calm, which helps depict the peaceful African Serengeti.

In comparison to Killer Queen, this song is less disjunct in its melody but carries a sense of heartfelt passion in the chorus because the range of the melody suddenly gets a lot higher. Listen to the song in the chorus (1'16) and see the notation below which shows that the first note of the chorus is more than an octave higher than the first note of the verse!