Thank you very much zellkos! The music was made by my team mate Jorge, he is an amazing musician :D.
Thanks for the ammo system appreciation! I thought about an oxygen system but preferred ammo over that. Although I could have added both, I preferred not to add the oxygen to keep the game simpler and not having to think about refill (which would have been complicated because of the endless "going deeper" mechanic/parallax.
And yes! The difficulty increase over time, each 750 points sharks spawn time would decrease, so you would have to deal with more and more of them :D
My highscore is 8400 :)