I liked the 'recursive' nature of the game as you move from the blood cells towards the humans/armies fight, I thought this was really novel! The art also looked great and together with the music it was almost kind of trippy XD
I died at the "generals" stage and I wasn't sure what to do next, the level didn't auto restart and I didn't find any restart level button. I was also not sure at times if I was really controlling my units since they seemed to go in all kinds of directions... most of the time I felt like I wanted to select all of them anyways so you could potentially benefit from just turning into one-click game where you just point the army for where to strike. That's just a suggestion though!
Really well done putting this together!