TillyTally™
TillyTally™ is made by one person. Questions, bug reports and suggestions all reach the same inbox, and all get read.
No, and it is not going to. The app does not know how any game is played — knowing would mean being told the rules of every game a household plays, which is more work than it saves. You know who won the hand; this is somewhere to put the number.
Tap that round and change it. Every round is kept, and totals are worked out from the rounds each time they are shown, so the correction carries all the way through and nothing is left disagreeing with anything else.
The scoring set-ups that come with the app are traditional games only. A branded game's scoring is almost always one of the shapes already there — pick the one that matches and save it under whatever your family calls it. It will be waiting next time.
No. One person keeps score, which is how it works at a table anyway. You can send a finished tally to somebody else, and it opens in their copy of the app as a copy of its own.
Only by your device. Everything lives in the app's own storage on the phone, and if your phone backs up to iCloud or a computer then so does this. There is no account and no server — see the privacy policy.
Always. The app makes no network connection at all, so there is nothing to be offline from.