I love the concept! It felt cool being tiny and sneaking behind the short walls or going through tunnels. And it makes sense that you need to be bigger some times to make jumps or run quicker. Could be a really cool game with some more time.
My only suggestion is to let the character scale up and down without having to use the blue/orange blocks. That way the player has to think more about what size they need to be instead of the blocks telling them.
Awesome game! and thanks for reviewing Cell Life!