The game is quite enjoyable. The art is simple but good, the sounds were good as well, but there was no music in game. The UI was clean.
I like the atmosphere you were going for, being in a human body. I think you used the different cells perfectly, I love how sometimes I'm tricked by the white blood cells because they look kind of like the cells I'm trying to infect. I also like that the UI was minimalistic, it helps the atmosphere even more and was very useful.
I think that maybe the game camera is a little too zoomed in, it makes avoiding the pink cells a bit too difficult. I found a couple of small bugs, when I attach to the cell I'm supposed to infect, I can still move outside the cell without my virus shell. Also, sometimes when I die I respawn without the arrow indicators around me.
Overall, a very fun game. Good luck with the jam!