It was a bit hard to figure out how the purchasing system worked, but once I got it, the game was fun!

It's interesting that the optimal strategy is to wait until the last second to feed the blob (to maximize income). Normally, I would consider this a bad thing because it slows down gameplay and makes the player wait. However, there's something so satisfying about watching the blob expand and then suddenly shrink, so I don't think this should be "fixed".

I also liked how you had the purchased animals wandering around inside their boxes, rather than just standing still. That kinda stuff really adds to the experience!