Fantastic idea, great take on the theme, and a brilliant execution. Thank you for spending your weekend in (I can only imagine) a very hard battle with window managers and viewports, you've made a thoroughly enjoyable experience. More details:
Presentation: Simple, I LOVE the window bobbing up and down, such a nice touch, and the sound controls sitting there were brilliant. Sound design was excellent and effects felt satisfying.
Mechanics: Nice introduction of each mechanic. I got a little confused about what the icon for "window that scales the character too" was - but only for a minute or so, and then with enough fumbling around, I got it. Maybe introduce that in a puzzle where the player is forced to accidentally discover it, and make it glow, to show them what it's doing? Not sure, just nit-picking really.
I'd love to see other aspects of windows explored - opening new ones? Minimising them? Jumping off context menus? The possibilities are endless.
Overall, it's got the quality of a fantastic gamejam game: my immediate thought at the end was "MAKE MORE LEVELS!!!". Great job guys.