1. As the test phrase states, "...to have a chance to win...tap this sentence without any error." Does that mean that we can't make any mistakes to make a valid entry, or just that typing without errors will (by being faster) give a better chance of winning?
My previous answer implies that you can hear bips, retype the correct letter and continue. On the other hand, it is more in the spirit of the contest to assume that once you hear a bip you will stop, cancel and restart a new one.
In practice, it will not make much difference because any error and bip causes enough disruption to kill any chances of a record run. But the spirit is to keep only bipless runs. In the future we could revise FitalyLetris to mark with an asterisk (or whatever) runs that had a bip.