I like how minimalistic this is, with no clutter. It goes straight to its basic mechanics without hassle, and I think they are already quite complex por su a simple game (fishing, world travel, inventory management).
I found interesting that you used growing-and-disappearing squares to make the player feel that he's walking over water. It's such a small but meaningful detail... Also, onces the rod is being used, suddenly drawing the vertical depth was also a very comic-like way to resolve it; quite cool! Another detail I appreciated was to realise that fish had a given size, as you don't know this until the inventory shows up.
It is a chill, cozy, small game to get relaxed. The minigame with the rod combines sound with action, which multiplies the feeling of the actions. The deeper you go, the more you hear the thread going. Every time you try to catch it, the more clicks you listen. This might sound trivial but, as they taught me once, games must have sound or they render into lifeless moving images.