A war submarine vs a battleship. Who would win? Arrow keys to move. 1 to fire a torpedo, Hold 2 to fire a missile. (only when you surface) The missile has a cooldown of 2 seconds. If you get too close to the ship, it will fire a torpedo, which will explode after some time if it doesn't hit you. Depth charges will release a shock wave when they explode, so stay away from them Hard mode is 100% possible.
I got the Terraria music from https://scratch.mit.edu/projects/590926828.