This is really well made! Awsome! XD

Well Dude !! What an imagination you have !!
Awesome , But the frog is looking like slug!

That Tortoise is blasting some serious beats by the look of that face. :P
I like the goofy face and the colour changing outline you gave it, makes it very pleasant to look at.

Judging by the description you seem to think that you could have done this one a bit better.
If you ever decide to revisit this piece, I'd suggest moving the neck hole further to the left, as it seems as if though it is more to the side as opposed to the centre. I would also maybe consider making the tortoise wider so you could add more tortoise shell details to up the quality of the drawing. Longer legs would also make it so you could see the other side legs as well.

Lastly, if you decided to drastically alter this drawing, it could be to make it a Stereo Tortoise, with incredibly large speakers sticking out the sides. It would allow you to add longer legs and more impressive shell details, as well as to give you more pixels to work with as a result of the increased size of the canvas.

Just some suggestions, but either way I'm happy with it.
Thank you very much for the request and I wish you luck with the rest of your Pixel Month. :)