The CPC is a highly selective group that picks its own members and runs the country. That doesn't sound like democracy.

Also, new alternative parties don't exist. Are they allowed?

From Wikipedia:

While only the CCP holds effective power at the national level, there are officially eight minor parties that exist alongside the CCP. Founded before the proclamation of the People's Republic of China, these parties must accept the "leading role" of the CCP as a condition of their continued existence.