Spoiler warning, obviously!
With that out of the way, congrats! If you’re reading this you probably beat Yang for the first time. Unfortunately, Sifu takes a page from the Ghosts ‘n’ Goblins handbook, sending you back to the beginning for a second run. You don’t even get credits!
While the in-game messaging is nonexistent, there are specific tasks you need to complete in each level. Luckily, the tasks are the same. All you have to do is rematch every boss, and spare them instead of taking them out more permanently. But how does that work? It’s a little extra challenge.
For the most part, you just need to fight the bosses again. The first phases are exactly the same, but there’s a new twist to the second phase. If you can break the boss’ structure before killing them, you can choose between the normal finisher prompt, and a new one simply called “Spare.” Unfortunately it’s kinda easy to overshoot that target and accidentally kill your foe anyway, so make sure to be careful, watch those meters and mind those buttons.
You can take your time with this! You earn a specific item each time you spare a new boss, and the game considers the task done (similar to the detective board). Since Sifu saves your best run for starting each level, you can be as sloppy and reckless as you want to make the structure break happen. As you know by this point, blocking attacks still hurts structure, and the bosses sure do like to block a lot!
You can do all this in any order, but you have to go after Yang last. As you approach his room, there’s a set of walls you have to “look” at, which will react to your accomplishments and display symbols. Make sure to activate all four before facing Yang. After that, you’re all set to get some actual credits rolling, and the sense of accomplishment that provides.