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Graphically, The Sims 2 is more detailed than The Sims and lets players view its world in full 3D. Unlike earlier Sim games, such as SimCity 2000, which used dimetric projection and fixed resolutions, the camera in The Sims 2 allows the player to view things from many angles. Sims themselves are much more intricately detailed than they were in The Sims. In The Sims, Sims are 3D meshes, but The Sims 2 introduces far more detail in mesh quality, texture quality, and animation capability. A Sim's facial features are customizable and unique, and Sims can smile, frown, and blink. The player can adjust, for example, a Sim's nose to be very large or very small in The Sims 2's Create-a-Sim. Texturing is still achieved through use of raster images, though it appears more lifelike. Movements are more smooth, natural and true to humans and Sims are in general more animated.

Sims have new experiences unavailable in The Sims , such as aging and eventual death. Sims can become pregnant and produce babies that take on genetic characteristics of their parents, such as eye color, hair color and personality traits. Genetics play a huge role in the game, and as such, the dominant and recessive genes are playing a bigger role than they did in the original Sims game. So if you take a blonde sim and a black haired sim, the child will probably have black hair, because it's a dominant color. Additionally, babies in The Sims 2 progress through life stages to become adults, while babies in The Sims only become children before ceasing to continue aging.