Being as he is an extraterrestrial whose alien race was that of a vastly evolutionary and decidedly superiorly developed capacity his powers on Earth were significantly enhanced. The planet Krypton being already much further advanced on their own evolutionary scale also benefited from the fact that it had a significantly denser gravitation pull plus far greater electromagnet intensity of their Red Giant Star.
Both of these forces made the Kryptonian people already naturally biologically stronger than that of the strongest of any of Earth's inhabitants. Furthermore the much smaller yellow sun combined with a vastly different electromagnetic wavelength spectrum being generated, in this solar system would allow the already physically superior biological structure of the Kryptonian cerebral, skeletal and muscular advantages over the inferior Earthlings. His extremely dense alien molecular structure had evolved in a star system which had a red giant star as its power source. The combination of all these factors gave Kal el the amazing powers that we refer to as super.
His incredible powers of super speed, flight, enhanced super strength, heat vision and invulnerability were simply psychic thought control of his already highly developed Kryptonian brain generating its powers of telekinesis.
The powers of X-ray, heat, telescopic and microscopic vision are simply more focused and very precise versions of telepathy, clairvoyance and thought projection of those highly developed psychic prowess. These are evolutionary genetic enhancements which had been enjoyed by his species back on Krypton, only here they are more intensified by the influence of the yellow suns E-M frequencies.
The same is true for his super hearing! He can simply attune his advanced brain to mentally pick up on any frequency much like tuning a scanner and instantly be able to read the thoughts of those whom he focuses it on. So Telepathy is the source, which augments his already highly developed normal Kryptonian hearing enhancements here as well.
When one really analyses it, my friend, these super powers are simply those of an evolutionarily superior Human who has complete use of all his normal psychic abilities combined with some extraordinarily enhanced biological human traits in his physical, mental and emotion makeup . That is why he is "Superman"