Privacy
Short version: no accounts, no ads, no analytics, no tracking cookies.
In your browser
Cinderwake keeps a few things in your browser's local storage so they're there next time: your display and sound settings, the name you last typed for the leaderboard, and a random player id. The id is made up on your device; it isn't linked to who you are. Clearing your browser's site data removes all of it.
The leaderboard
When you start a run, the game asks the server for a run ticket. When a run ends and you submit it, the server keeps one entry per player id: the name you typed, the time you survived, your kills and level, and when it was set. Entries are public on the leaderboard.
To stop the leaderboard being spammed, the server also records the IP address a run was started from and when, and limits how many runs one address can start per hour. These records aren't shown anywhere.
Hosting
The game is served by Cloudflare, which processes requests (including IP addresses) to deliver the site and protect it from abuse, under its own privacy policy.