Computer game that enables hundreds or thousands of players to simultaneously interact in a game world through avatar. Typically this kind of game is played in an online and also named Massively Multiplayer Online Role-playing Game (MMORPG), multiplayer - only persistent world.

According to cognition psychology the construction of mental models comprises the acquisition of knowledge and the understanding of complex information. A mental model integrates pre-knowledge, facts and relations to an "image" which more or less corresponds to an extract of the real or possible "world".

See “Massively Multiplayer Role-playing Game (MMPRG)”

Games that are played on mobile (cell) phones. A number of different technologies are used:

1. Embedded Games are programmed to run natively on a phone's chipset, installed on the phone at the factory, and shipped with it

2. SMS games are played by sending a message to a phone number that corresponds to the game provider's serve

3. WAP(Wireless Application Protocol) games are played by going to the game provider's URL

4. Mobile J2ME (Java 2 Micro Edition) game are programmed using J2ME Java language optimized for small devices such as mobile phones and PDAs. J2ME is also an industry standard backed by many manufacturers.

Mobile games can also be developed in C++.

A type of MUD text-based virtual reality system. Usually MOOs (MUD object oriented) are used or role-playing games (RPGs). Most MOOs are now web-based, integrating the text environment with multimedia features.