I am making a Tetris clone with a new idea but I won't use the Tetris or Tetriminos name in the game I will refer to them as Tetrominos. Will there be copyright issues if I release this game? Does the Tetris company own the right to produce "Tetris" games?
"Tetris" is a trademark of The Tetris Company, LLC. Game mechanics are not patentable or covered by copyright, but the name trademarks "Tetris" and "tetrimino" (note the spelling) are theirs.
However, the company have been annoyingly successful at bullying simple clones of their game out of marketplaces using the legal system anyway, even though the legal standing of their claims to ownership of the exact playfield size and shape of pieces is highly questionable.