I love what i see in muscles layer and animation, but there are some issues with tissue sim. I cant say what is wrong, i can only guess...
I dont see those issues in muscle layer, so maybe you can do more investiogation there. I would check tet mesh resolution for sure!
If i compare same pose, muscles and tissue layer, you loose lot of creasing in areas where it bends. Not just legs, but all "bending" areas in general.
Adress this, and it will be awesome!
Hope this helps.