Unfortunately due to time constraints we weren't able to get that part of the art done in time :(
But as for the softbody slime, it was made up of a bunch of bones attached together with 2D spring joints! I used Unity's sprite editor to add bones to the sprite, and then added rigidbodies to them in the editor all with spring joints. It was a tutorial I found on softbody physics on YouTube that you may want to check out!