I'm guessing that you had probably played these games before & now you replaced the files with Xinchi's. You must have the save files stored in your system. Just delete those & you should be good to go. But if Xinchi's game files have unlocked game launcher then you need to re-modify them to its original state.
There are several ways how a flash game can be coded for unlocked contents & it differs from game to game. For JSK games, I have seen that THIS code was mostly erased in the actionscipts of the main launcher.
(Note that this is from Moody Niece & the code is in
スタートボタン_14 actionscript. The code can be in different timelines but its more or less the same in other games.)
In order to make that SWF back to it's original state, I'd say you'll need a fresh copy of the game & check which one of the actionscipts was modified.