When I first saw your submission my first thought was HOLLOW KNIGHT! As someone who studied game design your interpretation of the theme felt super relatable XD
What I thing could be interesting would be getting more visual/audio feedback on knowing which students to target. For my first run, I didn't really understand that I had to be shooting the students with the countdown above them and thought I caused the countdown, so a bit more feedback on how that mechanic works with something like a "ding" above the student could help :)