How can I replace laminate with polished concrete flooring?
The main problem you will have is thickness, thin concrete tends to crack. Your laminate flooring is all of 1/2 inches thick most likely, so the maximum your concrete floor could be is that much, and that's not enough. Other problems are:


unless you are pouring on slab the flexing of your floor will cause the concrete to crack
unless you are pouring on slab the concrete will drop between the floorboards
unless you are pouring on slab the floor will probably not be designed to take the weight and could lead to structural problems
Creating polished concrete requires special materials and repeated sanding with ever finer diamond wheels, equipment which would be very expensive even to rent, presuming you can rent it


I'm not saying it's impossible, if you're on slab you might be ok, but if it were me I'd be considering a cool looking tile rather than polished concrete.