An easy way to get this achievement is after you have already beat the game. Start a new game with your recent character and ONLY use the plasma cutter. I recommend doing this because you will already have known where everything is and what to expect plus some of your stuff will already be upgraded and you will most likely boughten some good armor. The plasma cutter is really the best weapon in the game it's versatile, powerful, and the ammo is cheap. Also because you are continuing a new game with your previously used character you can worry less about buying armor and you may already have upgraded your plasma cutter some. But use ALL of your Power Nodes to upgrade the plasma cutter and your armor. YOU DO NOT NEED TO FILL IN THE EMPTY CIRCLES IN THE UPGRADE MENU.
You can ONLY shoot your plasma cutter, you can still use stasis and telekinesis. You can stomp and hit but the only weapon you are allowed to SHOOT is the plasma cutter. So if you accidently pull out a different gun and you don't shoot it your ok.
Good Luck I don't recommend doing this on Hard or Impossible.