I was thinking about what’s unique to me. All I could think of at the moment was how I play grand strategy (a type of game where you play a country or some king)… would it be a good idea to write about gaming?
I have around 200 words written down if someone would want to take a look and advise how I could go from there.
I don’t think writing about gaming is the best way to highlight your qualities. I would suggest that you spend sometime thinking about who you are, what unique qualities you have and what makes you you? If you still have trouble figuring out your best qualities, talk to your friends, parents and teachers and find out what do they think about you. I think this essay might be a great chance for you to find yourself…All the best!
Last year I had a discussion with a student about that very topic.
My first comment then, as now, is that writing about gaming sends a bad message to admissions offices. They want student who will be out and about, interacting with classmates. They do not want someone who might spend four years in their room playing games. So anything that points in that direction could be a problem.
^ Interesting opinion. Would you feel the same about writing? Art? Reading? Coding? After all, socializing is the main point of college. 
What I feel is irrelevant. What is relevant is the view of the one audience that matters, college admissions officers. These folks are aware that a lot of students – particularly male students – get to college and do a lot of gaming. This does not make them happy. They want students who will take advantage of the academic and other opportunities their college offers and/or whose work will reflect well on the school. So, yes, college admissions officers would take a better view of solitary activities such as writing, coding, painting… pretty much anything other than gaming. This is simply the hierarchy of values in that world.
I think that if OP uses the essay to bring out some of their personal qualities and writes about the interaction between this sort of gaming and themself, it could work. Just be sure not to talk too much about how the game works or anything like that. The essay could also cast grand stategy in a light that the essay readers might never have seen it in before, which could make it stand out.
Start early so, in case it doesn’t turn out well, there will be plenty of time to think up and write another essay.
Bad essay topics:
Gaming
Depression
Mental illness
Politics
Substance abuse
“Explaining” any negatives about yourself/ your grades
Bad mouthing your school/ other people