My biggest complaint with the game is the story. Personally, I had no problem with the slow pace--although a faster pace would have benefited the game--but where this game really plummeted was the story. The beginning was a bit corny--because everybody who's different has to kill themselves, right? I chuckled a bit at "good G," but then was disappointed with the direction the story took with "evil D," whose name I didn't get until I read some of the comments...should have been "satanic S" or something. Anyway, this should not have been a damsel in distress story. If inverted Y had gone around the world helping people who once had shunned him for his differences, this story would have had a clichéd yet still much better message than what it has right now. Instead, we have a plot that essentially goes nowhere, often taking the wrong direction. The ending was especially rubbish and uncalled for (although, as a nonreligious person I wouldn't have gotten any obscure religious references), and the lack of better directions than "press spacebar to invert the world" is disappointing--because who would have thought that when you invert the world, certain platforms fall upwards, yet nothing else is affected?
The one thing about this game that was done right was the art style. The clouds, trees, buildings, and lightning were very aesthetically pleasing, yet it seemed once you entered the earth that these kind of things were wholly absent. Had there been mushrooms, stalactites/stalagmites, glowing precious minerals, and etc, this game would have been quite gorgeous. Perhaps these things could have replaced the rampant "x"s that currently exist underground for no reason.
So, in conclusion, this game is in need of some serious polish. The basic idea is in the right direction--letters representing ideas/characters--but it is surrounded by so much disappointment that it has lost its effect.