PEGI explained
The Pan-European Game Information (PEGI) age rating system was established to help European parents make informed decisions on buying computer games. It was launched in spring 2003 and replaced a number of national age rating systems with one single system now used throughout most of Europe

The system is supported by the major console manufacturers, including Sony, Microsoft and Nintendo, as well as by publishers and developers of interactive games throughout Europe. The age rating system was developed by the Interactive Software Federation of Europe (ISFE).

Age rating

The PEGI labels appear on front and back of the packaging indicating one of the following age levels: 3, 7, 12, 16 and 18. They provide a reliable indication of the suitability of the game content in terms of protection of minors. The age rating does not take into account the difficulty level or skills required to play a game.

PEGI 3
The content of games given this rating is considered suitable for all age groups. Some violence in a comical context (typically Bugs Bunny or Tom & Jerry cartoon-like forms of violence) is acceptable. The child should not be able to associate the character on the screen with real life characters, they should be totally fantasy. The game should not contain any sounds or pictures that are likely to scare or frighten young children. No bad language should be heard.
PEGI 7
Any game that would normally be rated at 3 but contains some possibly frightening images or sounds may be considered suitable in this category.
PEGI 12
Videogames that show violence of a slightly more graphic nature towards fantasy character and/or non-graphic violence towards human-looking characters or recognisable animals, as well as videogames that show nudity of a slightly more graphic nature would fall in this age category. Any bad language in this category must be mild and fall short of sexual expletives.
PEGI 16
This rating is applied once the depiction of violence (or sexual activity) reaches a stage that looks the same as would be expected in real life. More extreme bad language, the concept of the use of tobacco and drugs and the depiction of criminal activities can be content of games that are rated 16.
PEGI 18
The adult classification is applied when the level of violence reaches a stage where it becomes a depiction of gross violence and/or includes elements of specific types of violence. Gross violence is the most difficult to define since it can be very subjective in many cases, but in 
                   general terms it can be classed as the depiction of violence that 
                   would make the viewer feel a sense of revulsion.

Content descriptors

Descriptors shown on the back of the packaging indicate the main reasons why a game has received a particular age rating. There are eight such descriptors: violence, bad language, fear, drugs, sexual content, discrimination, gambling and online gameplay with other people.  
Bad Language
Game contains bad language

 
Discrimination
Game contains depictions of, or material which may encourage, discrimination
 
Drugs
Game refers to or depicts the use of drugs

 
Fear
Game may be frightening or scary for young children

 
Gambling
Games that encourage or teach gambling

 
Sex
Game depicts nudity and/or sexual behaviour or sexual references

 
Violence
Game contains depictions of violence

 
Online gameplay
Game can be played online