Answer: Tetris

Tetris, the wildly popular video game based on rapidly stacking tetranomial shapes, is the most widely ported game in the entire world. As such, it is no surprise that it was none other than Tetris that made an appearance as the first game featured on a cellphone.

Tetris appeared as the first mobile game in 1994 aboard the Hagenuk MT-2000, a phone designed and manufactured in Denmark by the Hagenuk corporation. In addition to sporting the first mobile game the MT-2000 also featured the first built-in antenna and was one of the first phones on the market to feature soft keys.