The differences at the photoreceptor level have been addressed by others. Another restriction of the visual system was shortly hinted at by @gilhad and deserves more attention in my opinion.
In darkness we cannot focus on an object and our eyes will move. And even when we focus on a specific point there are microsaccades. Microsaccades are involuntary small movements of the eye. It is thought that these movements prevent adaptation at the retinal level, and prevent image fading. Hence, images on the retina are constantly mechanically refreshed. The brain in turn stabilizes the image by correcting the image at the perceptual level through oculomotor feedback.
While a camera must be fixated on a tripod stand to allow for overexposure, our eyes cannot be fixated, even when we try. Hence, combining exposures as indicated in the question is impossible and results in image blur. Instead, retinal images are constantly refreshed and when lighting conditions are too dim we cannot integrate photon input in the temporal domain.