Fun Fact: Hundreds of thousands of copies of Tengen's version of Tetris were destroyed after Nintendo won an injunction asserting their sole right to publish the game.
There were two versions of Tetris published for the NES. The second one chronologically was published by Nintendo. For four weeks before this, the original version published by Tengen was on the marketplace, and this is usually acknowledged as the superior version. If you are building an NES collection, this is the version you want to hunt down as it bore a much closer resemblance to the arcade version of the game.
Tetris was a puzzle game originally and famously designed by the Soviet Academy of Sciences. It was simple but addictive. Random block selections were dropped into the play space, and had to be matched together by color. Put enough blocks of the same color together and they would disappear. The blocks would be introduced into the play space faster over time, until eventually the blocks would spill out of the play space and the game was over.
Tetris is usually associated with the original Game Boy handheld, as it came packaged with the system and played a huge role in popularizing it, but the Tengen NES version was just as well-regarded by the gaming community.