Just finish the last level and you get the "Piece of Cake" (complete L.A. Meltdown on any difficulty or in co-op) Achievement<br />
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Also it has already 100 kills in Multiplayer so try to play a ranked match and see if the multiplayer 100 kills achievement also unlocks.
Duke Nukem 3D [Last Level - Piece of Cake] 04/06/2016
Duke Nukem 3D [Last Level - Piece of Cake]