Last one to post in this thread wins!
Sorry, but I doubt that you could sand your concrete floor smooth. I'd use a floor leveler, which is basically just thin cement. To use, clean your concrete, then spread a layer of concrete glue, looks like wood glue, probably in same section of the store. Then pour your leveler on top, finishing it just like regular concrete.
https://encrypted-tbn3.gstatic.com/...AmWoYPvBMIKWOAI1k77Pg52DjjP5KzTGX9x5QiokCXhzw