If you are looking for something other than the indie game, "Cosmic Cube" also refers to:

While the character designs and backgrounds are praised for being "nice" and "flashy," the lack of a tutorial makes basic mechanics difficult to learn. Steam Status & Delisting

An in-game unlockable system for cosmetics that uses earned currency.

Reviews for the game (v1.07 and earlier) generally describe it as a short, unpolished indie title with high-quality artwork but significant technical flaws. Critical Game Observations

A specific mission and boss fight content update featuring the Cosmic Cube. Cosmic Cubes Review | SpeedCubeShop