That could possibly be something about your system and not the games, actually. Especially if it happens with many games.
What OS are you running these games on?
Do you have Python installed on your system?
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Nevermind, I just got the same error trying to load an old save in the new version of "Little Sister".
It seems to have something to do with the Ren'Py SDK being downgraded for the new version of the game:
Version 0.1 of the game was built on Ren'Py 7.3.5.606 and I had 2 save files created there.
Starting the newly released version 0.3 of the same game and trying to load one of the old saves gave me the same error:
Code:
While running game code:
File "renpy/common/00action_file.rpy", line 452, in __call__
renpy.load(fn)
ImportError: No module named matrix
...and full traceback follows.
Since it reports about a missing module, I suspected that Ren'Py SDK may have been upgraded by some new buggy version, but what I actually discovered was that the new version of the game has been built on Ren'Py 7.1.3.1092. It means that Ren'Py has actually been downgraded and save files created by a newer version of Ren'Py can't be loaded because the older version is missing a module that exists in the newer one.
One way to play the new version of the game that has been built on a downgraded Ren'Py version is to start the game from the beginning.
The other one is to upgrade Ren'Py to the version that was used for the previous version of the game: copy folders "renpy" and "lib" from the older version of the game into the newer version and overwrite existing folders and files. Then these old saves that were actually created by a newer version of Ren'Py will work again without the missing module error.
In this case both the new version and the previous version of the Broken Dreamers have been built on the same Ren'Py 7.2.2.491. I'm guessing that the previous compressed version was upgraded to a newer version of Ren'Py by the person who compressed the game and now saves created there won't work with an older version of Ren'Py either in the uncompressed original game or in the new compressed game that hasn't been upgraded to the newer version of Ren'Py.
You should open log.txt file from the previous compressed version of the game and look at the Ren'Py version number. In case it's newer than 7.2.2.491, then I was right about the old compressed version running on a newer version of Ren'Py.
In that case you could copy "renpy" and "lib" folders from that old version into the new one to upgrade Ren'Py to the same version that created those save files.
