Hey cool stuff, i have some C&C if you can use it, took some time off to draw over your design to help give you a visual of how he can pop more.
The basic and general idea here big forms for this little guy i feel will go along way.
Here is an animated gif showing what i am talking about, it is rough but the general idea of bigger forms across the entirety of the design is shown.
Hope it helps, will check back whether or not you take these critics, looking forward to the cart.