Off to a really great start and has a lot of potential, though could use some more features to spice up gameplay and add replay value.

Animations are fairly fluid, though at larger sizes/faster movement speeds it skips a little between running and falling when moving over uneven terrain.

Movement is also pretty fluid, though is easily interrupted by small ledges (e.g., sidewalks, baseplates, road edges), particularly at smaller sizes.

Shrinking should be gradual similar to growth, allowing players to better regulate size. Alternatively, both growing and shrinking should have "hold" and "rough" options.