THIS IS MY OPINION
1. The artstyle:
In any pixelart media, be it a picture or a game you should have the same pixel size at every sprite, your background shouldn't have the pixels bigger then the sea shells or palm trees else it will look pretty weird/bad which was sadly also in your case, find a median and dont stretch the sprites.
2. Sound design:
The sound effects are pretty annoying, they are loud and play often, you can try to use softer sounds, using variation and quieting down the volume.
3. GamePlay:
Imo the game is too repetetive and not fun at all, its a point and click game and isnt fun to many people as theres not much gameplay happening. This is just a genre "problem"
Again this just my opinion so take it with a grain of salt