I'm going to dispense with the bold-face headings for a bit since the last section was titled Jesus Christ Please Save Me From This Autism and I think that is going to be an appropriate title for a while yet. Just assume that that is the section we are on until I tell you otherwise.
Okay, so. At this point in the story, Silver has Glimmyglam pinned down on the floor. An interesting detail that I didn't notice before is you specifically mention him slamming her face into the "crystal" ground. If I'm following the increasingly convoluted sequence of events correctly, what happened is, Silver "genie of the weenie" Star asked Ponk to pull a party out of her ass in Applejack's barn for Twilight, summoning everypony except Twilight to the party (whether or not Applejack was ever consulted about the use of her barn is never mentioned but whatever, that hardly matters at this point). The purpose of said party was to distract Twilight to keep her out of the house while clones of Silver rob her of all her worldly possessions so they can install a new hot tub (a detail that isn't explained until later, all we know presently is that Silver's doppelgangers are ransacking her house). Whether or not Twilight is actually attending the party is still unclear. Silver sees Glimmer at the party eating cake and minding her own business and decides to randomly attack her because that's what any reasonable pony would do, causing the party to stop with a literal record scratch.
So, if I'm following this correctly, this scene should be taking place at Applejack's barn, right? So why is the floor crystal? Why mention that detail? Why would AJ's barn have a crystal floor? I mention this because the only place in Ponyville I can think of off the top of my head with a crystal floor would be Twilight's castle. Are they supposed to be in Twilight's castle now? The very castle that is being ransacked by the clones, that Twilight, for whom this party was thrown, was supposed to be kept away from? Because the way it looks to me is there are only two possibilities: either the party has inexplicably moved to Twilight's castle, or the eternally practical AJ had a crystal floor installed in her barn for some unexplained reason. Neither scenario makes sense. Explain yourself.
Anyway, next Rainbow Dash, so far the first character you've introduced who does anything sensible, becomes angry at Silver "hot cross my buns" Star for randomly attacking one of her friends and charges him full-speed. Naturally, one of Silver's thousands of powers is to somehow become a rigid body incapable of being moved regardless of force, described "as if he were made of titanium" in the text, so of course Rainbow crashes into him and falls to the floor without doing any damage or even moving him slightly. Considering Rainbow's famous speed and strength, it seems like the effect here would be similar to crashing a car into a retaining wall; I find it hard to believe that Rainbow wouldn't have sustained some sort of serious injury. However, I'm just going to chalk this one up to cartoon physics and move on.
Naturally, another of Silver "Squeeze me I'm full of custard" Star's thousands of powers is to perform some kind of Vulcan mind-meld with a ghost version of himself that springs from his horn and allows him to read the minds of other ponies. Oh, also this:>Meanwhile, his spell was just one of many ways he could read her. Light blue numbers and lines appeared in his sight and he saw her heart rate, the size of her pupils, her pulse, her brain activity, and if she even twitched a little, anywhere on the body, a subconscious muscle contraction that would tell him she would be about to move or lie, he would know.
So I guess he also has cyborg eyes or something. Naturally. So, anyway, he reads the thoughts of Rainbow Dash and notices that her mind is answering questions differently than she answers them verbally, or some other kind of crazy shit like that. Hm, sounds like the game is ahoof, Dr. Watson. How is our super-sleuth going to get to the bottom of this mystery?
This is my favorite part. Starlight Glimmer, apparently deciding that the line of questioning is delving too deep into her past, volunteers her entire backstory as a justification for her actions. Silver listens to her, and is surprised to discover that he can't get angry enough at Starlight Glimmer and finds himself wondering why.
I have to say, that is a twist worthy of M. Night Shyamalan. Of all the developments in this story I would have expected, your OC, who is endowed with every superpower in this or any other universe, being unable to be as angry as he would like at Glimmer is not on the list. Could this be his kryptonite?
No, it isn't. Turns out that actually, Glimmer is some kind of anomalous being, a creature with the ability to warp reality around her and force ponies to like her, and apparently she does it without realizing it. Nopony is supposed to actually like her, they just like her because they are forced to. Her entire redemption is explained away with this flimsy device, thus setting the stage for Glimmy to be justifiably beaten to a pulp by the ever righteous Silver "I swallow if I'm thirsty" Star. Before we get to that though there's a paragraph that frankly deserves an entire post dedicated to it.
Oh, also: it looks like you do specifically mention Twilight "proudly" watching SS and SG make up (though she doesn't intervene in the fight), and the barn is again mentioned, reinforcing it as the location for the scene. So, looks like Twilight is at the party, and AJ's barn has a crystal floor. Whew, glad we cleared that up or I wouldn't have been able to sleep tonight.