X-Out

From the depths of outer space to the depths of the world's greatest oceans came the alien forces of Alpha Centauri. Out of their savage attacks on all air, sea and land borne craft grow the united efforts of the world's super powers: Project Deep Star – the ultimate underwater war machine. Deepstar increases in power and weaponry with each vicious encounter. Now you are called to command. Build your craft from the credits you hold, destroy the continuous onslaught of aliens and your credits increase, so to does your power to end this threat to mankind.

Source: TheGamesDB