Super Robot Wars OG Gaiden (スーパーロボット大戦OG外伝) is a 2007 tactical role-playing game, and direct sequel to Super Robot Taisen: Original Generations, for the PlayStation 2. The bonus segments of Original Generations, entitled Original Generation 2.5: Unified Wisdom, was regarded as a preview for Original Generation Gaiden. The game resolves many matters left unchecked at the end of Original Generation 2.5, such as one of the main antagonist s unfinished plan and the activities of one of the enemy factions.