Best way i've always looked at it is, Shrooms and DXM are both psychedelics, but project your perception in opposite directions. Shrooms and other tryptamines tend to propel you forward into hyper-reality, in which your sensations are all boosted and especially enhance your understanding of visual, tactile, and auditory senses. Shrooms tend to shift your consciousness in a manner that amplifies your surroundings and current emotional plane, sending you into sensational oblivion. DXM, and other dissociatives, do the exact opposite. These substances tend to propel you backwards, away from yourself, so that rather than heightening your emotional complex, they diminish it. Your vision will begin to see less of reality, rather than more of it, you will not be able to hear more of reality, rather your auditory sensations will begin to distort and flange. It also reduces your ability to feel tactile sensations greatly, and thus often results in a diminishing perception of gravity.
To sum it up, I look at everyday reality to be viewed in a pseudo-1st person perspective, or 2nd person. You sort of tell a story about yourself. Shrooms and other tryptamines propel you into the 1st person, in which real time is experienced seemingly for the first time ever, in which you live out your experiences directly. DXM and other dissociatives tend to shift you back into 3rd person mode, in which you observe your actions from a distance.
Both can be fun or scary, introspective or extroverted experiences. But in general, i think this sums them up nicely.
Think sensory overload versus sensory deprivation. Both can produce vivid hallucinations.
