I couldn't quite understand how to move my game forwards, so I kept dying. But the concept is pretty unique and really cool! Not being able to know where your enemies are at all, and needing to echolocate them is really cool. Also the "stealth" idea to turn off your engine to be less noisy. My only issues with the game was understanding what were enemies or what were their torpedos/attacks, and if I could hit them at all.