The first Prototype Alex Mercer had enhanced his senses in two ways. Mercer had developed Thermal vision which granted him impeccable vision during battle where thick smoke would otherwise impeded his vision, but would also help him see his targets due to their body's temperature.
His second sensory ability was the Infected vision, which allowed him to detect dormant carriers of the Blacklight virus, while providing similar tactical advantages of the thermal vision.
Some Evolved, such as Sabrina Galloway and Roland, developed sensory powers or those related to them. The former developed a power akin to Heller's hunting ability, whereas Roland developed the ability to be undetectable from such a method.