The slide through the last patch of hearts seems to sometimes result in one more or one less heart than usual. Seems like the Apple Arcade version (at least) is much more generous with riskies. This may be true for the Switch version only. Pausing right before that section seems to help (something to do with changing which frames the game checks for near-collision), but it's inconsistent. The riskies from the giant swords that fall from the sky are very stubborn. 53 results from getting the entire middle row of hearts while curving back and forth enough to have the bike leaning over enough to grab hearts from the outside rows for 11 out of 20 hearts in the row. 52 is a bit more consistent, but 50 or 51 is much more common. Near the beginning when I curve back and forth through 3 rows of hearts, the most possible hearts you can have by the end of that is 53, but I've only managed that a handful of times. This level has a few tricky/frustrating places: Mine, like all boss levels, also has a couple of places where you need to mash the button.

In addition, there are 'style points' that come from getting dangerously close to an obstacle (Risky!) and moving a certain distance continuously in one direction (Slide!), which are worth 50 each.

Big hearts start at 25, coins start at 1000. Each item makes the next of that kind worth more - the first heart is worth 1, the second is worth 2, the third is worth 3, etc. Scores in SWH are primarily made up of points from collecting little hearts, big hearts, and square coins. Mine is the fourteenth level of the game Sayonara Wild Hearts, wherein we face off against the Stereo Lovers for the last time.

Sayonara wild hearts mine square coins