I have checked it over and am unable to find the grammar mistakes you are speaking off, could you specify where they are so I can fix them?
Aight I'll take a crack at this. Pedantic English teaching skills GO!
First, lemme preface this by saying "grammatical" language is different from "standard" language. It's entirely possible for one to be correct for one, but unnatural or "wrong" in the other. Grammatical is "language we actually use," while Standard is "language as told by 'the rules.'" They aren't the same thing. This will be important to keep in mind for what I'm about to correct.
You are "X", you have lost your recent memory.
This should be either two separate sentences or rephrased differently. Examples: "You are "X." You have lost your recent memory." or "You are "X," someone who has lost their recent memory." I would go with the first, but in general the way this is phrased is very unnatural.
Waking up in a room you do not recognize.
This statement is a non-sequitur. It doesn't really connect to the previous sentence or the sentence that follows. To put it another way, it doesn't "flow." Sentences like this are a big red flag to me of people who don't have a huge grasp of English.
It should read something like: "You wake up in a room you don't recognize."
English is REALLY big on needing subjects and objects, which is why we English speakers pretty much suck the cock of pronouns to such an insane degree. Having a sentence without a subject works in some languages if the subject was in a previous sentence, but in English it only works if you're being poetic. And to be that poetic you need one HELLUVA good grasp of English first.
Try and find out what happened, what is this place and who you are.
I will give you props that this sentence was definitely written by the same person who wrote the previous two. This is faint praise but consistency can be a good thing.
Unfortunately, making a consistent mistake...isn't really a good thing.
This one's just unnatural, so I'll fix it a bit: "You need to try and find out what happened, as well as what this place is and who you are."
By exploring, collecting photos and finding notes about the past.
I'm addressing this one separately because I really need to hammer this point home that English needs subjects to make sense. This sentence not only lacks a subject, it lacks an entire grammar form.
It should be part of the previous sentence, which should now read:
"You need to try and figure out what happened, what this place is, and who you are by exploring, collecting photos, and finding notes about the past."
It's a bit of a long sentence and I would revise it quite a bit if I were giving this more than a cursory glace, but this accomplishes what you need to do.
Anyway yeah this is why I recommend that people who don't speak a language natively hire a proofreader if they want to make a project to distribute to people who speak that language. Just because you THINK something is grammatically correct and isn't triggering spelling/grammar check in whatever word processor you're using, doesn't mean it's a grammatical sentence.
Also gonna reiterate that the game's title is a massive "I don't speak English" red flag. If you want to specify the Facility owns something, try going with a title like "Of the Facility." But it really should be workshopped. Dangling possessives like that are a red flag. The only exception is things like names for restaurants and bars like "Joe's." But those almost always use proper nouns.