So, what do you get if you combine Defense Grid with Portal? A really amazing DLC. The maps for You Monster are very different than the maps in any of the other Defense Grid DLCs. First, it's based off Portal complete with insults from GLaDOS. Second, a lot of the maps are more than just stopping the aliens, GLaDOS interferes by limiting what towers you use and so on. If you like Defense Grid and Portal you can't go wrong with this DLC.