Simple DS Series Vol. 46 – The Hikyou Tankentai – Choujou Special ‘Kyoui! Jinrui Mitou no Sekai Kakuchi ni Nazo no Mikakunin Seibutsu wa Sonzai Shita!!’ (Japan) is one of the best Nintendo DS retro games you can play free online — no download required. Jump straight into the action from your browser and start playing in seconds.