Super Robot Taisen OG Saga: Endless Frontier is a story-driven turn-based role-playing game and spin-off in the Super Robot Taisen series.
The player takes the role of Haken Browning, a bounty-hunter living in the world of Endless Frontier – a world connected by portals called Cross Gates (or Kokuri-mon). While exploring the remains of the old forgotten space ship with his personal female robot and friend Aschen Brodel, he discovers a strange life form - Mild Keil crystals – and find a girl from across the portal. They learn that she’s a princess in her world and decide to get the bounty for returning her home. However this doesn't happen – upon arrival to her world – Kagura Amahara - the bounty hunters learn that mysterious Mild Keil crystals are spreading there too and that some people and creatures are brainwashed in their presence. The princess Kaguya joins the party to investigate the cause… Four more people and intelligent robots will join the party throughout the game. The party will also meet smaller copies of robots from the original series.
The battle system resembles Namco X Capcom - another title developed by Monolith Soft. The battle screens looks like a 2D fighting game. Upon selecting the desired action in menu a character will engage in combat with enemies, linking his moves in a chain, executing combo breaks etc. if the attack button is pressed at the right time. If the player misses the attack pattern the enemy may engage in evasion maneuver and counter-attack. Longer attack combinations build up the Override gauge which allows to execute exclusive override moves. The attacking party may only consist of 4 people, all the rest are put in the back row and can be called to help during the fight.
Some characters from Namco X Capcom and Xenosaga series make their appearance in the game either as party members or as antagonists. The game features a lot of humorous and frivolous dialogue and images.