I beat level 1! I feel like I cheated a bit using the solid red walls to bite and launch haha :)
I like this game. Inside the body is definitely a unique environment, lots of room to take this further for sure, and I would definitely be interested in playing more levels. As for constructive feedback, If you want to take this forward I think you could definitely look into what kind of visual juice you can add around background textures/layers, particles (especially things like fluids etc), camera stuff, etc.
I know this isn't a gameplay round, but I did enjoy the mechanics, it was difficult but not super frustrating, I think you got a good balance which can be difficult in a gamejam.
Great entry! And congrats on your first solo jam!