very nice! this is a very high quality implementation of the laser guiding style puzzle game. nice clean graphics style. going with monochrome was a good choice that also adds a feeling of melancholy.
the main improvement i'd like to see is more challenge. i felt like finding the solution was too easy, just clicking on mirrors in order. played long enough to see new mechanics introduced like the splitter, the sliders, the teleporters, etc. but i felt like they never really ended up making the puzzle any more complex.
i think the difficulty problem comes down to linearity. working from the start in a linear fashion solves every puzzle without much logic required. maybe this could be helped if there were more ways for players to fail. like instead of just the parts necessary for the solution, have some parts that are only there to distract and open up the possible combinations.
overall though really great work, it's a beautiful game and improving puzzles can always be done later after you've had more time to experiment with the mechanics. sound design is also great. awesome work!