I haven't created any patch notes due to how extensive the changes are. In essence its the same game. re-built from the ground up. At the same time a lot of new stuff has been added as well. Most of the original maps have returned, again recreated from scratch. The first level for instance is almost a 1:1 recreation with some small new areas added.
I reckon the most radical change is the customization feature which has been greatly expanded upon. Down Town is a completely new map that adds vehicles to the game and Little Big Catventure is a new level set inside an apartment where everything is huge (think rat maps). Cat bells are thrown around every level that if you collect a certain number a new wearable item is unlocked.
And then there are small interactions that are there to add to the role play aspect of the game. The goal of the remake was to make the game just better overall and be a much more fun experience. Character movement has been improved as well and I've added small improvements and additions throughout. It's hard to really explain the difference because it's a remake I didn't want to go too far with changes, yet I took the chance to make the game a much richer experience if that makes any sense.
So, I guess it's safe to say that if you played the original you know what to expect it's just that everything feels new and fresh and it has two completely new levels. I'm not completely done either. Two older maps will be making a return soon and I have plans for further updates in the future as well.
I guess the closest I get to a patch notes list is the game's play guide which you can check out here:
https://steamcommunity.com/sharedfiles/filedetails/?id=2352598832
Hope that helps.