No account, no password. The code is just random words and numbers: nothing about you is in it. It's always under Stats if you need it.
Your stats are saved on this device. Clearing your browser or getting a new phone can erase them. Your save code brings them back.
Take a screenshot, or bookmark your personal link:
Finish a game and your save code will show up here.
Enter your save code. Any stats on this device will be combined with it.
What's saved: your scores, streaks and which puzzles you've played. That's all. No name, no account, no password.