Answer:

BATTLESHIP

Answer	Crossword Clue
BATTLESHIP	Two-player game
BATTLESHIP	Part of the game, and the game itself
BATTLESHIP	Guessing game

BATTLESHIP	Target board game
BATTLESHIP	Typically gray vessel
BATTLESHIP	Missouri or New Jersey.
BATTLESHIP	The Oregon, for example.
BATTLESHIP	Game
BATTLESHIP	Shade of gray
BATTLESHIP	It may have the name of a state
BATTLESHIP	Off-shore fortress

BATTLESHIP	It's four units long in a popular board game (with the game's other pieces hinted at by the circled letters)