In order to access this game, you must get to the point in the game where you beat the Karma Society Tower boss Heat. Once all the cutscenes are over with and your back on your feet near the Egg facility, go to the Underground City and talk to the little girl who says, "Do you wanna play a game?" Suprisingly, Atlus put some time into this shmup for what its worth.
The game consist of the character Cielo who's element power consist of Lightning. The game gives you a slow shot by pressing square(This form takes off middle damage of the enemies), A rapid fire shot by pressing X(This is the weakest shot), and a uppercut slash by pressing circle(takes off the most damage but has very limited range).
The scoring system gives you a multiplier gauge on the bottom left of the screen. This gauge has 4 divisions and you bump up the multiplier by using the slash attack on enemies. The best way to bump up the multiplier is by slashing "purple enemy fire". The rest of the enemy fire cannot by destroyed so you have to dodge. Once this meter is maxed out, you have a limited time to score X20 with every enemy defeated.
The game consist of many different enemies from the Digital Devil Saga universe and they all have their unique attack patterns. There is only 3 stages but each stage has its own unique enemies and bosses. The graphics resemble that of other vertical arcade shumps such as Shikigami No Shiro but not nearly as detailed. The backgrounds are very generic but the enemies is where most of the graphic emphasis was put into.
The purpose of this minigame is to beat stage 3 with a score higher than 30,000. It is nearly impossible to get points in this game unless you utilize the scoring gauge as mentioned earlier. If you manage you beat the game with the highest score, you will get an item that customizes karma rings in the main game.
People who are a fan of the Shin Megami Tensei universe and love shmups, then you have to check this minigame out. Go get yourself a copy of Digital Devil Saga 2!