I really enjoyed the simplicity of this game, and the eye movements of the pet really help bring it to life! I think there is a simple code to make the eye movements interact with the mouse, adding that could give this game a nice layer of interactivity that I believe could really make it a lot of fun, if you want to keep the minimalist style. Another thing I would recommend would be some sort of goal, it could even be something small like the color of the sprite changes when you have fed or played with it a certain amount. Currently, I do not understand if I am feeding or playing with it for a certain reason, a level/progress bar could help with that a lot, or some form of numbers at the top, or even if the pet decided to say something when it had eaten enough food or something like that to let me know I was succeeding in some way. Sorry if this is a bit confusing!