I really liked this short because it shows clearly and in a beautiful (and painful) way how a gay kid comes to discover his feelings, all without needing a long time for everything to unfold. I also really liked the choice of making Chul Soo part of an acting class - I believe it delivers a powerful parallelism.
I'm keeping this review vague when it comes to the plot because, as a short movie, I believe it can't be said much without spoiling almost everything. All I want to say is that it hits very hard, and it might hit much harder if one had a similar experience as a queer child. The entire movie feels so plausible that I wouldn't be surprised if this was based on a true story.
The acting was incredibly good. I had no expectations since the main actors are all children, but Nam Hyeong-Jung delivered an amazing performance. The piano pieces of the OST also match the different scenes very well.

I recommend watching if you have the chance!