With the thcrap patcher and fan translations, this is playable in a bunch of languages, and runs well on Linux and on the Steamdeck.

As a bullet hell game it's easy to get into, has simple mechanics, is very replayable with the huge differences across the difficulty levels, and playing to the scoreboard (and only seeing the ending if you reach it without using a continue). Cirno's charged attack that freezes bullets is a super fun ability: it's defensive, it's offensive (your bullets get stronger and it lets you stay in position to shoot), it fits the very strong theme, it can be fully charged for a long freeze or fired early as a tactical save.

Cirno's cause is also just: an evil conspiracy is destroying fairy houses in order to force fairies to unite under one flag! The connections to real-world geopolitics are, of course, obvious! It was very brave to publish a story like this, and I hope that Cirno's example resonates with players, of how best to respond to plotting like this.