1. Artistic Styles

2. Photorealism
Photorealism is the genre of painting based on using cameras and
photographs to gather visual information and then from this creating a
painting that appears to be photographic. The term is primarily applied
to paintings from the United States art movement that began in the
late 1970s.
As a full-fledged art movement, Photorealism evolved from Pop Art
and as a counter to Abstract Expression as well as Minimalist art
movements in the late 1960s and early 1970s in the United States.
Photo realists use a photograph or several photographs to gather the
information to create their paintings and it can be argued that the use
of a camera and photographs is an acceptance of Modernism.
http://en.wikipedia.org/wiki/Photorealism

3. Photorealism

4. Cel Shading
Cel shading (often misspelled as 'cell shading') or toon shading is
a type of non-photorealistic rendering and an illumination model
designed to make computer graphics appear to be hand-drawn.
Cel-shading is often used to mimic the style of a comic book or
cartoon. It is somewhat recent, appearing from around the
beginning of the twenty-first century. In addition to computer
graphics, it most commonly turns up in video games. However,
the result of cel-shading has a very simplistic feel like that of
hand-drawn animation. The name comes from cels (short for
celluloid), the clear sheets of acetate which are painted on for
use in traditional 2D animation, such as Disney classics.
http://en.wikipedia.org/wiki/Cel_shading

5. Cell Shading

6. Abstraction
Strictly speaking, it refers to art unconcerned with the literal
depiction of things from the visible world it can, however, refer
to an object or image which has been distilled from the real
world, or indeed, another work of art. Artwork that reshapes the
natural world for expressive purposes is called abstract; that
which derives from, but does not imitate a recognizable subject
is called non-objective abstraction. In the 20th century the trend
toward abstraction coincided with advances in science,
technology, and changes in urban life, eventually reflecting an
interest in psychoanalytic theory.Later still, abstraction was
manifest in more purely formal terms, such as colour, freedom
from objective context, and a reduction of form to basic
geometric designs.
http://en.wikipedia.org/wiki/Abstraction_(art)

7. Abstraction

8. Exaggeration
Exaggeration is used in games, mostly in RPGs, this art style is
used for animé and manga typically, this art style is where the
artist exaggerates many things within the game, mostly games
with a Japanese influence, for example, in the game "final
fantasy 7" the character "cloud" has a huge sword.