Here's the beta of the moment:
https://nickydicky.itch.io/test2?secret=gxYwI4mWFcD0dhEjV8HCaL0dqs
Neither my friend nor I tested it this time, so I have no idea how it is. All I know is that it's the fight against Muchen, apparently, at the last save point, instead of the game ending, it sends you straight to the fight against Muchen, skipping all the content in between and the fight against the twins.
As for the full update, the twins' fight still needs to be reworked, as well as the post-fight and a few other details. Nicky's optimistic estimate is 5 days, but to be conservative, I'd say one or two weeks.