While it is a bit disappointing that Mugen Souls has been delayed until October in North America, to help ease the disappointment slightly, NIS America have also released this battle trailer which over two minutes details the games battle system – including both the normal battle system and G-Castle Space Showdowns.
Back when the game was released in Japan several months ago, I picked up a copy and back in April wrote one of the first English-language reviews for the game which can be read HERE.