Connoisseurs of the composer's oeuvre of the earlier (youthful) creative period pick out as the most successful works his Laudamus (Slavoslovije), cantata for solo voices, mixed voice choir and orchestra; Sinfonietta for String Orchestra (published by Breitkopf und Härtel), Zlato / Gold, a mime ballet with singing and orchestra; the brilliant, bravura Concerto da camera for Solo Soprano, Violin and Seven Wind Instruments (published by Vienna's Universal Edition) and the most important Croatian religious works from the end of that period of Papandopulo's creativity – the oratorio for solo voices and a male a cappella choir Muka Gospodina našega Isukrsta / The Passion of Our Lord Jesus Christ and Hrvatska misa / Croatian Mass for soloists and a cappella mixed voice choir.

The origin of part of Papandopulo's oeuvre of the 1960s and 1970s is related to his guest appearances and acquaintanceships with musicians in the then divided Germany (FRG and GDR), where he had opportunities to meet outstanding artistic personalities, as well as recent European musical creation.

Ideologically grounded aesthetic worldviews never inhibited Papandopulo in his choice of non-musical subjects for his own works; he always found, in each one of them, universal ideas, profound human values.

At the same time he would write compositions of religious topics – from the Croatian Catholic mass with traces and elements of Glagolitic chant (Osorski rekvijem / Osor Requiem, Pučka poljička misa / Folk Mass from Poljica, the cantata Jubilate and a number of smaller religious works) and also monumental works of socialist realism (inspired by the ideology and poetics of the post-war socialist revolution and the People's Liberation War, such as the musical-poetical work Pasija po srcu / Passion After the Heart, the poetic-musical vision Credo, 1943 – cycle of songs to words by Ivan Goran Kovačić) as well as those inspired by Croatian history (the cantatas Libertas, Pohvala Dubrovniku / In Praise of Dubrovnik, Non bene pro toto libertas venditur auro, Mile Gojslavica and the triptych for mixed voice choir and large symphony orchestra Istarske freske / Istrian Frescos and so on).

Atom”, Kraljevo, Prsten / The Ring, Menschen im Hotel, Der Königsreiher) have demonstrated their anthological values in the many repeated performances at home and around the world.

A large number of his works feature an authentic and typically Papandopulo buoyant and infectious musical humour (in a large range from tonal play full of brightness to flippancy and rough musical grotesquery) in which he often quotes themes of other authors (Grotesque for Tuba, Piano and Percussion, Pop Concerto for Two Pianos and Orchestra, Magic Flute, Papandopulijada, Divertimento alla pasticcio and so on).

This particularly refers to anthological compositions of Croatian concertante and operatic music, some of which he revitalised and put on the stage in his own arrangement (some of the works of Lisinski, Zajc and Krežma, for example).