Maybe a good idea to disable bilinear filter on fonts meant to look pixelated. Liked the game over all but i didn't find the tutorial levels all too helpful
Keep the first level and introduce division on that one, also keep the cross breeding one and the virus one. Then make new levels that help us learn how to figure out the differences between the cells and the interesting behaviours that may come out of complex ecosystems.
I imagine big part of the game can be creating a setup in sandbox mode and see what happens upon changes like temperature, figuring how the cells behave little by little, but it may be confusing and hard to make sense of to some people, appearing rather random, so explaining a bit in the tutorial would be great.
Also consider adding a slider like temperature that makes food auto-spawn and changes how often it happens.