Just the achievement of having completed the game is fine.

needs a sprint button or faster movement overall

I retrieved the little fish and threw the cage back in the water, but the exit won't open no matter what, even if I play the horn. What am I supposed to do? Did I miss something? Please someone tell me because having to redo everything from scratch is pretty annoying, so I want to be sure I do everything correctly next time I try....

idk if its supposed to do that or not but when i brought the cage up the ball just rolled/popped out of the cage and back into the ocean?? can't seem to do anything else?

I'm having trouble figuring out what to do to start the game. I'm stuck in some kind of room on a ship and I can mess with a crane, fiddle with the steering, or press a button to temporarily open a hatch that I don't know the purposeof. Haven't really figured out how to actually start the game...