Summon Night: Twin Age is an action-RPG (Role Playing Game) developed by Flight-Plan for the Nintendo DS.
The game heavily uses the DS's touch-screen to play. The gameplay is pretty easy to understand. It is similar to most MMORPG (Massive Multiplayer Online Role Playing Games) games like World of World, Ragnarok Online, Rose Online, Trickster Online, etc. You touch the enemy and your character attacks it. At the beginning of the game, there is a short tutorial that will help you understand the game. While playing the game, you get to have character that is controlled by an AI. The AI is somewhat good, sometimes it kills itself my going to into a mob of monster and they also stand on places that reduces their HP (Poison, Spikes).
As for sound, the BGM is pretty dull. The game has a lot voice acting, so the characters repeats the same thing over and over each time the character is using a spell or attacking an enemies. It could be annoying sometimes especially if you do not like the voice.
The graphic are pretty neat. It has an anime (Japanese Animation) style artwork. If you like the anime style characters, you might play the game without liking the gameplay. However, if you like the cute anime style, this game is a complete turn-off for you.
The game has a story and it has story each characters. If you want to want to know all the stories of each character, then you would want to replay the game multiple times to find out.