In building commercial jobs I have found one phrase that keeps comming up, especially when talking about concrete floors and all ceilings. "water level"
I know, its almost impossible with concrete but one friend of mine said he would 'give a nickel' on the concrete finish; if a nickel laying in a low spot on the concrete was not covered with water, it passed.
The rental store has a gasoline powered concrete grinding machine. It has 2 circular apparatuses with 3 concrete grind stones on each one. It works a little like a buffer or trowelling machine. Keep the stones wet for long wear (they will still cut just as much, but without the dust). Remember, if you wear the stones out you have to replace them before the rental store will take it back.
Laminate flooring is thin and will telegraph any irregurlarity. It may take an hour or two of grinding to make it satisfactory but, believe me you'll be glad you did.