Added【achievement】features and F12【screenshot】function and【Steam Deck】verified

If you completed the game after January 2nd, you will automatically receive the achievement upon opening the game. If you completed the game before January 2nd and do not wish to complete it again, you can use the following method to modify the save file to obtain the achievement (the following methods will be deleted after 7 days):Open the save file, usually located at C:\Users\user name\AppData\Local\PIS
Add the following content:
[Progress]
Cleared="1.000000"
good_end="1.000000"
normal_end="1.000000"