Being one of the large 'ALL' islands, this one Still does not seem to be the most difficult, because modern composer differences sound more pronounced than for example Romantic. [All Modern]

Very simple comparison of most known baroque Handel and modern Schoenberg. Schoenberg sounds romantic or dissonant. (Handel, Schoenberg)

Please see my comments for islands with pairs of these three composers.

Use language to guess vocal. (Messiaen, Schoenberg, Webern)

Schoenberg's Pierrot Lunaire has characteristic vocal bends. Moses und Aron, Survivor from Warsaw include many german declamations.

Only Messiaen has piano songs, organ in this game.

Schoenberg is 12-tone except for Guerrlieder Vorspiel in this game. Guerrlieder has a different late-romantic Wagner sound.

Messiaen sounds rhythmic, repetitive, less dissonant, atmospheric, oriental, tonal percussion.

You can use language to distinguish vocal pieces. (Messiaen, Schoenberg)

Only Schoenberg has string quartet+vocal, sextet (Verklarte Nacht), piano concerto in this game. Pierrot Lunaire has characteristic vocal bends. Moses und Aron, Survivor from Warsaw include many german declamations.

Only Webern has piano songs, piano with strings, choir cantatas in this game. Webern Two Early Pieces for Cello and Piano, Im Sommerwind, Langsamer Satz, Passacaglia, Rondo, which sound very romantic.

Schoenberg is 12-tone except for Guerrlieder Vorspiel in this game. Guerrlieder has a different late-romantic Wagner sound.

Watch out for Webern Two Early Pieces for Cello and Piano, Im Sommerwind, Langsamer Satz, Passacaglia, which sound very romantic. (Schoenberg, Webern)

Only Schoenberg has string quartet+vocal, sextet (Verklarte Nacht), piano concerto, orchestra pieces in this game. Pierrot Lunaire has characteristic vocal bends. Moses und Aron, Survivor from Warsaw include many german declamations.

Only Berg has string orchestra, violin concerto, clarinet+piano.

Schoenberg is 12-tone except for Guerrlieder Vorspiel in this game. Guerrlieder has a different late-romantic Wagner sound.

Berg combines Mahler romanticism with 12-tone technique.

Berg Lulu and Schoenberg Moses and Aron operas include piano. (Berg, Schoenberg)

Only Schoenberg has piano concerto in this game.

Schoenberg is 12-tone except for Guerrlieder Vorspiel in this game. Guerrlieder has a different late-romantic Wagner sound.

Bartók is atonal + folk and sounds less chaos. (Bartók, Schoenberg)