Nice work! Great concept, really cool art, music, sfx! All top notch. It definitely fit the theme through and through.
My only critiques would be the controls were a bit wonky. I could work through them, but at times it definitely felt like I was fight the game engine rather than controlling it.
My other critique is a spoiler, so stop reading now if you haven't played!!!
(I'll try and leave out any big descriptions, but the final "memorial" scene, after you complete the last level, seemed tonally dissonant from the weighty feeling the rest of the art, music, and events expressed. I guess this is a your-mileage-may-vary moment, but that one animation felt almost comedic, after feeling very heavy and sad. But this may not bother other players, so eh. Just my two cents.)
A really good entry overall though! Great work.