Well seeing as we exist within the third dimensional plane we would be completely crushed if we were to enter the second. All of your bones and organs would be completely flattened, and you probably wouldn't even feel the pain since all of nerve ending would have been cut in half depending on where the 2D plane is lying. Also if we could somehow survive within a two planed world we wouldn't be able to see or smell or hear because sight is based on the refraction of light, which can only be interacted with in the third dimension, not to mention scent and sound which are mostly based on waves and chemical reactions. Scent, arguable, could exist but it would not be any form of scent we are familiar with, nor would it travel int he way scent travels in 3D because the laws of physics themselves would be for the most part gone. Interestingly enough we could theoretically travel into the fourth dimension and have our being intact, since the combining variable of each dimension carries over consecutively into the next.