Our Pymetrics practice games that measure an ability end with a score out of 100. It is our own measure of how you did on that run. On Keypress it is built from how many times you pressed, how fast and how evenly you kept pressing, and how much you slowed down in the second half. The real game shows you nothing, so read the score as feedback on your own rhythm rather than a target. Every game weighs things differently, so compare a score only with other scores on the same game.
After a game we also show a percentile: the share of saved practice sessions on that game that your score beat. The chart below shows the same kind of spread, counted more strictly (see how we counted, further down), so it will not match it exactly.