This cage has very easy access! The homemade shelf (cardboard and linoleum) is held in place by tie-wraps. If the shelf is removed, you have an excellent large one-level hospital cage (pic above). Depending on how the cage is decorated, it can easily be made suitable for rats with impaired climbing abilities (pic below, with a wide slanting ladder and fairly low hammock).
Disadvantage: The wire bar spacing and loose top make it unsuitable for small rats!