The OVA series was meant to give perspective on fictional events happening in the "real world" outside the game.

The OVA series is based on sections of the first two volumes.

It was adapted in 1997 into an OVA series.

An OVA series based on the novels was released from 1992 to 1993.

It expands upon the events covered in the first two episodes of the 1988 OVA series.

The OVA series consists of 6 episodes which are - except the last two - independent from each other.

This version is 45 minutes shorter than the OVA series.

Many of the characters are similar to those in the OVA series.

It spanned 3 episode OVA series and ran in 2004.

An OVA series was released in 2003, with three sets of episodes.