Cube MetalHeart is a multi-player shooter using the Tesseract Engine. It's an extended version of Sauerbraten, like a standalone mod. Featuring new content and backward compatibility to Sauerbraten maps and servers ! Music by lukhash.com
Very good improvement on the original Cube 2 game. Highly recommend trying this game out, as it's also one of the better free (open-source) games out there.