This can make his works seem a little heavy-going until one acquires a feeling for Rung´s technique and manner. Everything points to a highly-developed and personal style of playing.
His virtuoso technique and serious attitude towards the guitar as a concert instrument probably resembles the approach to the instrument represented by his teacher Söffren Degen at the beginning of the 19th century. Unfortunately we know all too little about Degen´s technique and playing-style. He instructed Rung in the art of guitar-playing despite the fact that he was younger than Rung. Degen entered Siboni´s music conservatory in Copenhagen as a pupil at the age of 13 and as regards musical training was thus considerably ahead of his colleague.
The suggestion of folk music in many of Rung´s compositions comes from his use of a very simple kind of harmony and part-writing with emphasis on the melody as the most important element. His extensive use of four-part writing and his way of carrying through the voice-leading, together with his fondness for small character-pieces consisting of a melody with very simple accompaniment, all indicate, it seems to me, that his ideal sound must have differed markedly from that of his southern-European colleagues. His very classic and conservative way of writing was probably inspired by the chorale-style of C.E.F. Weyse. It was no doubt here that Rung´s concept of musical sound was moulded.
Rung´s technique is most clearly seen in his Études (Petit lecons). All the études are provided with a four-part chorale, based on C.E.F. Weyse´s chorale style, in the key of the étude and demonstrating its underlying chordal material as a preliminary exercise before embarking on the étude itself. These études do not differ essentially from those of F. Sor´s Opus 60. We see here a very simple and well-sounding style of playing which is free of effects - there is no sign here of trills or showy arpeggios. A clear melody with a simple and effective accompaniment are features to be found in all of Rung´s music for the guitar; these are the virtues of a true master.

Henrik Rung (1807-1871), article