This is a really neat tile puzzler! The second-to-last level was pretty tough (the one with the two fish and two red dogs), but it felt good to finally figure it out. In general this is a really cool concept for a tile-based puzzle game.
There’s a ton of potential for mechanics similar to the “fish helps you swim” mechanic, which I thought was super cool. Specifically I love how you use that mechanic in the last level. This mechanic in conjunction with the “last monster gets released” mechanic makes me feel like there’s a huge design space here to explore. Really nice job!