The soil looks fairly wet and there appears to be some rotting stems. I'm not sure if this is the right time of year to re-pot but if you decide that's what you want to do, (depending on the size of the root mass) I'd suggest using the same size container or one only slightly larger and use a well draining soil, specifically for cacti and succulents. You can add extra perlite to the mix which will allow more air circulation around the roots and proper drainage.
