Thank you for the detailed and thorough feedback mate!
The insight with the sonar upgrade is really useful- it'll be one of the first things I add in the next build, thanks!
The x axis flip should be pretty easy to implement too, that's going on the list.
I wanted to go down the sprite sheet route for some nice idle/casting the hook animations, but ran out of time.
Having the sea move and/or having something in motion towards the surface is an excellent thought too.
Once again, thank you so much for taking the time!