Proofreaders and feedback needed for Two-Sided Mirror

You'll definitely need to hire a proofreader at some point. Just skimming it over, there are plenty of mistakes and rough spots.

Mostly though, I don't see the selling point. The concept feels like it hasn't been fleshed out yet, so neither the artwork nor the theme really engage me.

Concise and intriguing are more important than intensive. Take a look at "Falling" by Cheap Ass Games. It's free to print and play last I looked. Nothing complicated. "Each of the players is a person falling to his death. The goal is not to live, rather just to be the last one to go splat." That's all the story there is, but damn, that's all anyone needs to feel intrigued.

To give you another example, a key technique for writing good science fiction is that you change one single thing in an otherwise normal world and explore all of the ramifications that arise from that. Past that, the more you change, the more the reader has to strain their suspension of disbelief. If you make too alien of a world then the reader has no familiar landmarks, there is no way to know if it will rain battery acid or if anything has any significance whatsoever. With a game, you have to tread even more carefully, because while a vibrant and imaginative setting is mandatory and players give generous leeway, you can't stress players with an overly complicated backdrop while they are already trying to absorb the rules of play.

Just going by the first paragraph of your rulebook, you establish the setting as being on an alien world, reference a relic that may as well be called a magic lamp for all that it does, and make a disjointed reference to a bit of history that doesn't tie things together. What would a mirror have to do with a war fought over food, or perhaps fought with it?

People will often include a short fiction blurb to address these sort of issues, as this allows you to engage the senses and give the reader a sense of place in a few short sentences. Off-hand example:

"Rory tread lightly across a field of emptied mustard bottles, discarded relics of the Great Food War that he'd fought in as a young man. They were one of the few things that the desert winds of Toh had failed to grind down into dust. Every time that Rory spit out a mouthful of accumulated grit, he knew that he was also expunging trace remains of dead compatriots and fallen enemies, their bones nothing more than sand on the horizon. Yet, if the stories were to be believed, that sand had also polished the legendary Two-Sided Mirror to such a fine sheen that it had become a window to other realities, ones that you could reach through and touch. He could pull back a handful of wishes. He could bring life back to this wasteland.

"Rory spotted movement ahead in the wreckage of an overturned mayonnaise truck. He readied his whatever it is that people use to fight on Toh, and slunk into the shadow of a monolithic mega-spatula. He'd have to spread a little more dust before there'd be any hope of a miracle."

I've really changed my approach to game design over the past few years by simply thinking about the win condition and then moving backwards.

That may or may not be how you developed your game, but I think that including the win condition, as well as how the game ends, if not obviously tied to the win condition, is vital to me and other average people understanding what should be important.

Now, there may be all sorts of nuances and strategies that are 'under the surface', waiting to be discovered after playing through a few times, but a new player should have a clear idea about how to win a game - am I trying to collect 10 VP, be the last to hit the ground, or being the first to some kind of finish line? Only once a player knows his or her goal will they be able to understand why collecting Ore and Lumber is important (those resources let you buy VP-generating Settlements, for example).