Squished the last bug I could find, where the reversed character graphics wasn't be able to push rocks and reveal frogs.

For those interested:
@ =  rock with a frog under it
% =  surprised frog sitting in a divit revealed under the rock
$ =  pushed rock, now firmly settled
, =  shadow on grass, as cast by a tree, house, or rock.

The rules underneath are repeated because the rock should be allowed to be pushed over to both empty grass and grass with a shadow.
It all functioned mostly as intended.

BUT

I had written
[ > Player PlayerRight | @ |   ] -> [  Player stationary PlayerRight | % | $ ]
[ > Player PlayerRight | @ |   ] -> [ Player stationary PlayerRight | % | $ ]
[ > Player PlayerRight | @ | , ] -> [  Player stationary PlayerRight | % | $ ]
[ > Player PlayerLeft | @ | , ] -> [ Player stationary PlayerLeft | % | $ ]

Instead of

[ > Player PlayerRight | @ |   ] -> [  Player stationary PlayerRight | % | $ ]
[ > Player PlayerLeft | @ |   ] -> [ Player stationary PlayerLeft | % | $ ]
[ > Player PlayerRight | @ | , ] -> [  Player stationary PlayerRight | % | $ ]
[ > Player PlayerLeft | @ | , ] -> [ Player stationary PlayerLeft | % | $ ]

This repeated the topmost rule allowing the PlayerRight graphic to push a rock unto empty grass.
But it meant that the PlayerLeft graphic was only able to push a rock unto a shadow, which was rather confusing behavior!

Classic silly oversight when offhandedly doing the "plumbing" while adding graphical flair.