Interesting...
This game seems like a fairly standard point and click adventure. Theres nothing overly difficult about it and its fairly straightforward to play through (even if the story seems to get batshit crazy!) so it shouldn't take too long to complete.
The story here is kind of convoluted but that probably stems from the strangeness of the story in the first place, and the bad English in play throughout the story. When characters talk, sometimes you need to read it through a couple of times to make sense of it as it is very poorly worded. And in a game like this, that could be a dealbreaker!
I liked some of the little touches here, such as the room with the bright light streaming through the windows. Your character raises their hand in this room to shield his eyes from the light, and I liked how this immerses you more into the game.
The story at the end was a little strange though as at first your're told you need to restore the mirror so that you can leave and get back to the real world, but that is quickly forgotten about when Sara is just able to (hit you? never really see what she does to you) and you wake up back in the classroom. And of course this leads to the branching path for the two endings.
In what is probably the laziest way I've ever seen to introduce multiple endings, the character comes across a note asking them to meet them on the roof and all will be explained. You either select yes to this to find out the real ending, or no to have your character decide it was all a strange dream. This "alternate" ending seems like a throwaway really as its just tacked on for seemingly no reason. The real ending is much more interesting. It turns out the "Mysteryman" who was helping you was actually the bad guy! This is a shocking turn of events! Or possibly one of the most cliche twists used in games/movies to try and make you shocked.
The boss fights here were quite out of place for a point and click game, and it wasnt clear what to do right away. There was a screen to show what to do for each part, but the first one was accidently skipped past since I clicked on it trying to click the boss (as you would do in a point and click game...) The second part was especially aggravating because of a tight time limit for the clicks and poor implementation of it since sometimes i was DEFINITELY clicking the hands but still registered as a miss and I was hit. This led to a game over the first time and at this point I should bring up that you should definitely make the REPLAY button a whole button, and not just the text being clickable, especially when using a font as thin as the one you used. This is a simple fix, but its still something I find annoying.
So, overall this game is a promising start. It's rough around the edges, but they can easily be polished smooth for the next chapter. The biggest thing you need to work on however is the writing for the game. The English her just isnt very good, theres no way around saying otherwise. Whether this is because English isn't your first language (this is more than likely) or some other reason, you need to find a way to make it more coherent, especially with a plot going as batshit crazy as this one seemed to be going! I look forward to the next one though!