zOMG! is an MMO made for Gaia Online, a social website that allows users to create anime-style avatars to represent themselves in forum discussions and other activities. In this game, the player controls their avatar in a fight against the Animated, inanimate objects that have been mysteriously brought to life and become aggressive towards all other living things. The sole weapons that can affect the Animated are strange Rings that feed on the wearer's emotions to produce magical attacks.
Players may wear up to 10 different rings, each of which has a Charge Level, or CL, from 1.0 to 12.0. A ring's CL is a measure of how powerful it is, and the player receives their own CL that is the average of those of all their equipped rings. Rings can become more powerful by being fed Charge Orbs dropped by enemies. The player's CL affects their likelihood of receiving item drops from defeated enemies, with those at or only slightly above the player's level giving the greatest rewards.
Combat takes place in real time, and involves the player targeting a single enemy or ally at a time with their equipped rings, though some rings provide area effects and do not need to be targeted at any particular entity. As the player fights, they build up a rage meter at the bottom of the screen, and may choose to boost any given action with rage to make the resulting attack more powerful. Each ring has its own cooldown meter that depends on what type of ring it is.
The game world is divided into several themed zones, each designed for players of a particular CL range. Each area contains a Null Crystal, which links to a hub area called the Null Chamber. Through the Chamber, players can manage their equipped rings and instantly teleport to any non-instanced zone.
Players may group into temporary crews of up to six. Crews can chat privately with one another, enter instanced areas together, and keep track of their members on the in-game minimap. A player is removed from their crew after leaving the server. The other main advantage to playing in groups is G'hi Energy, which charges whenever the player is near large groups of other players and provides passive buffs until it runs out.
On September 30, 2014, zOMG! was taken down for maintenance to fix a critical issue. On November 6, it was announced that the game was not going to return from maintenance, due to security vulnerabilities that could not be fixed because of hardware and engineering limitations. However, the game was reopened on March 13, 2017, following Gaia Online's change in management.