A lot of Debian-based installations have an inactive root account. You are not meant to login as root. This is the case with Sparky, too. Or did you have to type two different passwords at installation? I didn't. The password of the first user created is the password for administrative tasks (using sudo or gksudo, see https://wiki.debian.org/Root
I would avoid setting a password for root which you can do with
sudo passwd root
I tried that two years ago on LMDE. After giving root its own password you actually have two different passwords (root's password and your password as an administrator). As the window which asks for the password (when starting synaptic, setting a new network connection, etc.) doesn't give a hint which of the two passwords is needed for the occasion, you type the wrong password half the time. This is really annoying. I ended up giving root my user password (basically like before, but technically you - unlike before - have two different, but identical passwords which both can and have to be changed individually).