"Is it a bird...? Is it a plane...?"
Does it look like a bird or a plane! I mean seriously!
He's supercharged and he even has a NOS switch.
Watch out Mr Hare! Tortoise has been pimped.
Comments appreciated.
(".)

This concept has it going on!

I'd like to see the wheels better.
I'm guessing you used only one color
on the design so that leaves you with
3 more - so you can use ...

... black to bring out the tires
... light brown to match the ground/sand being kicked up
... turtle/tortoise green for the head

The kicked up trail of dirt/sand could continue
toward the shoulder 2-3 more inches to make the
speed beast look like its going even faster.

You Go, Turtle !

Idea is not too bad... but the execution... I realy cant recognize the turtle here