I've been adding more content, but this modifies the game's code, making it incompatible with the save file. Therefore, you'll have to move the save file out of the game folder or delete it, but you'll lose your progress. :(
But first try to delete the "sinnerangelssavegame" to delete the game and then in the level selector load from the last checkpoint and if it works you will only have to complete the level to which it sent you to recover your progress, but if it does not work you will have to delete the "sinnerangelgamedata" to delete the checkpoint and losing all the progress.