Portal 2 accomplished the impossible feat of living up to the monumental expectations set by the original game.  The gripping single-player experience introduced new and even more memorable characters—namely Wheatley—and expanded upon the gameplay by introducing new mechanics like gels, light bridges and aerial faith plates.  The inclusion of a two-player co-op campaign was the icing on the cake and that’s no lie.  But for those of you who do not have any friends, don’t fret, as you can clearly see from the video above, many of the co-op levels can indeed be completed alone, by yourself, with nobody else...for science.