(I've got permission to post this, ask Moegreche.)
Here is the mod page with the link and the details (Sonny Wiki).
-Rebalanced abilities, leveling, classes, items, teammates, enemies, and re-spec.
-New classes, abilities, enemies, stages, items, drops, training fights, strategies, menus, and story.
-More accurate descriptions/info.
-Fixes, bonuses, extras, references, easter eggs/secrets.
Version 2.0 (2022 August):
-New classes (with their own skill trees) and abilities.
-Rebalanced enemies, drops, and abilities.
-3 extra starting ability points.
-Tooltip now shows negative values properly.
-Minor fixes and visual changes.