Abyss

so um, after a long descent straight down from roughly 650m (right next to the first 32 sized fish) to 1km without any fishes, I found the submarine, but in the end I'm pretty sure that the tiny secret passage I thought I found was just a hole in the wall, and that I'm not supposed to be under the wreckage 

actually there's even a second hole at 800m :o

I like the game, it simple but DEEP