Goop is very good! The name paired with the idle animation really sells this amorphous, sentient blob, and particular shout out to that eye poking the goop out at the top. It's small, but I love it. The pizza eating animation being super quick too really works in the games favor, especially with the big Feed Goop button at the bottom. I can feel how important it is to feed Goop, even without any context.
I will say at first I didn't notice the bar was changing colour as I expected it to shrink in size or slide off screen. It also would have been nice for Goop to change a little depending on how you feed them, maybe growing larger as they eat pizza or having the animation speeding up as they look for food, but I'd also understand if the unchanging nature of Goop was important to the concept.
Really excellent work overall, and an incredible amount of atmosphere with the relatively sparse assets.