Full playthrough here:
First off this is really well done especially for someone who hasn't done much in game development. Some of the things I can remember there may be more suggestions in the video. Swimming downwards or which way the fish is pointing. Check points would be nice since the game is a bit lengthy and the last phase can be a bit tough with the submarine and the frame perfect gas vents. I also got humped into oblivion up against a wall by a jelly fish which was not as cool as one might expect. I took the lost friend to the secret place and it seems like there was a hidden dialogue box that didn't spawn since I couldn't boost like when other fishes talk to you. I had a shark chase me down and murder me while a fish was talking to me about his gateway and I couldn't move. If you can figure out how to do it putting an downloadable executable version of the game would be really great as well since browser versions can have issues. I loved the dialogue in the game I honestly wish there was more it's pretty clever and enjoyable. Overall though like I said this game is unexpectedly fun and well done I love that you added a final boss and descriptions for the garbage you can pick up.