Funny story about T-Cell - basically the player character is the only one I implemented 4 directional sprites for... I did have 4 directional sprites for the mitochondria and nucleus as well, but then when I realized it would eat to much of my dev time to focus on that, I just had the npcs all just be front facing. I drew T-cell in a way that made it a bit easier to swallow this, as you can see he has multiple eyes and multiple mouths that go around his head, technically his sprite is always in the correct direction, unlike nucleus and mitochondria.