The most recent version of Assassin's Creed Chronicles: China on Steam has a bug in Memory 1 in which you can't assassinate 2 guards that stand in the way unless you restart the checkpoint which loses time.

An older version does not have this bug. Other version differences regarding the speedrun are not yet known (February 2020).

Through the Console in Steam you can downpatch ACC:China to the older version.

• Open the Steam console: steam://nav/console
• Type in "download_depot 354380 354381 2776973091873958211" and press Enter (these numbers can be found on steamdb.info and refer to the (1)app_id, (2)depot_id and (3)manifest_id
• Wait for Steam to download the depot. It will download the old version of the game with its full ~3GB. You won't see any indication of progress, but you can tell it's downloading by looking at the network usage on your downloads page. The download can pause/resume if your connection goes out, but won't if you restart the client.
• After the download is done, Steam will show you where the files were downloaded to.
• Go to the game's installation directory (C:\Program Files (x86)\Steam\steamapps\common), and move or rename the original "Assassin Creed Chronicles China" folder. Then go to where the depot files were downloaded to, and move everything over to the game folder.