Nuke Defence is a Tower Defence type of Game. Use different skills to kill the oncoming monsters. When they are destroyed you can collect the gold they drop and improve your three primary skills or learn brand new ones from one of the four major areas. Be it passive, fire, cold or earth. You can only have three of the non-passive abilities in use at any one time if those abilities are not enough, buy artefacts which will aid you in battle from dwarven boots to an arcane tome plus many more.
Use WASD to move, 123 to select your weapon and your mouse to place your attacks and shoot the monster invaders. F opens your skills options.