Philosophy
A puzzle is a quiet thing. You sit with it, you think, and eventually it gives way. Almost nothing about that needs a server, an account, or a notification arriving at the moment you finally see the answer.
You pay once and you own it. There is no plan to cancel, no renewal to forget, and nothing inside the app trying to sell you something else. That means the app is finished when it is good, rather than when it is converting.
One puzzle a day is free, at the gentlest level, for as long as you like. It is a fair way to find out whether you enjoy the thing before paying for it, and it is not a trial that expires.
The apps make no network requests at all. Not for analytics, not for crash reports, not for fonts, not to check whether there is an update. The puzzles are generated on your phone by the same code that grades them, so there is nothing to fetch and nothing to send.
This is easy to claim and easy to check: put the phone in aeroplane mode and nothing changes.
There is no account, so there is no password, no email address on file, and nothing of yours sitting on a machine we own. Your progress lives on your phone. If you delete the app it goes with it, which is the honest trade for never having handed it over.
These are made in Denmark, by one person, in no particular hurry. Three games share one engine room — the same sound, the same four places, the same promise — so a fix in one arrives in all of them, and none of them has to be rebuilt from scratch to exist.