This is a pretty cool game, it seems we had similar ideas for games about hiring divers. :)
The game loop was fun enough to have me hooked until I bought everything, it seems once you have 70 divers and all the plots there's not much left to do. The shark attacks made me wish the divers had some ability to get an upgrade to defend themselves, controlling the submarine was a little chaotic during the attacks, and the command sounds from clicking played over each other at a rapid pace.
It also would have been nice to see how many levels each upgrade has, or to disable the button when it is maxed out, to be more clear to the player about their upgrade path. You could add a sound for cashing out to improve the audio feel as well.
Some kind of final purchase or ending scene would also help signify to the player that they have reached the apex of their farming capacity.
Overall, fun entry and good job.