Really nice art and progression of mechanics here. I do think the game could switch vibe when the watchers are introduced, like having the boppy music loop switch up to a dark, ambient one would be amazing. To me it would become a game of two halves almost, like the first bit is a tutorial and then the world almost opens up to much more...
Having a separate sprite for the watcher when the shark is on it would be nice too! the eye being squished closed by the weight of the shark...
Overall though super nice!