This is among the impressive entries that don't look at all like your typical Game Jam fare when people get just one weekend, and whoever decided to make it a month long jam might have been on to something... even if you did still upload it at 11:59 in true Game Jam style :)
I'll echo GoodL's comment that your tutorials were really helpful, and in my case showed me how to set up the preloader correctly with a minimal init scene followed by a true preloader scene.
I see you have a lot of stuff you already plan to add so no need for me to make more suggestions there; the only comment I have so far is that by the end of the tosses the fish is moving and bouncing awfully slow so I might recommend harder stops at the end and/or keeping more horizontal velocity near the end so the player gets the feeling like the fish is still making decent progress until then.