Here is the full list of all 21 Touhou Multi Scroll Shooting 2 achievements.
Clear stage 6 with Reimu on any difficulty.
Clear stage 6 with Reimu on Normal or higher difficulty.
Clear stage 6 with Reimu on hard difficulty.
Clear stage 6 with Marisa on any difficulty.
Clear stage 6 with Marisa on normal or higher difficulty.
Clear stage 6 with Marisa on hard difficulty.
Clear default route of stage 6 with Sakuya on any difficulty.
Clear default route of stage 6 with Sakuya on normal or higher difficulty.
Clear default route of stage 6 with Sakuya on hard difficulty.
Clear "Special route for Sakuya only" on any difficulty.
Clear "Special route for Sakuya only" on normal or higher difficulty.
Clear "Special route for Sakuya only" on hard difficulty.
Clear Extra stage with Reimu on any difficulty.
Clear Extra stage with Reimu on normal or higher difficulty.
Clear Extra stage with Reimu on hard difficulty.
Clear Extra stage with Marisa on any difficulty.
Clear Extra stage with Marisa on normal or higher difficulty.
Clear Extra stage with Marisa on hard difficulty.
Clear Extra stage with Sakuya on any difficulty.
Clear Extra stage with Sakuya on normal or higher difficulty.
Clear Extra stage with Sakuya on hard difficulty.