Nice idea! Once I understood what was happening to the sea creatures (at first I thought they were buggy with that back and forth movement) I freed all of them.
Managed to clean 30 pieces, I thought the collider to get the trash felt a bit weird, but since there was a lot I always managed to pick something.
The movement of the diver felt a bit juddery, it usually happens when you move a rigid body outside of the fixed update loop the physics use in Unity, but since you used Godot I have no clue what could cause. It's a very minor thing anyway.
The graphics were alright, I liked the wavy effect of the screen to give the underwater feel.
The songs and audio effects were alright, but maybe there could be something more upbeat when you freed the animals?
Overall I found it a nice little game. Could be expanded in some ways, like allowing the diver to get more oxygen, fishes getting "re-trapped" by falling junk. Stuff like that! Also, on the credits in the main screen you mention art with quotes. I wouldn't use those quotes! It's art still and far better than most of us programmers can create in a timely manner! Congratulations!