Awww :)
So cute pets!
I think you really did it, this game had really nice n' cute graphics, and sounds were relaxing and it fit with the game and stuff. Gameplay wasn't really much great, it was fun but over time it got kinda boring. Moveing the mouse up and down, and from side to side, is boring after a while... :p
For a sequel, maybe you could make a 'story-mode' :) Challenge too, but you gotta add a story-mode-thingy.
I dunno exacly how, but I can give you some tips..:
At the start, you can choose from some type of pets, and colour, name, etc.
And different pets = different difficults :)
Only 1 pet in story, and maybe it's growing over time, and you have too keep it healthy, happy and -alive-... Maybe a store-thingy, buy toys, food, medecines, 'funiture', etc. Mini-games (like... I dunno ><) could be a kewl way to earn money ^^