The number of differences varies from level to level in Old Rusty Cars Differences 3, but the game will notify you when you've found all the discrepancies.

Unfortunately, Old Rusty Cars Differences 3 is an online game and requires an internet connection to play.

If time runs out before you find all the differences, you can still continue the game, but your score may be impacted by the time factor.

Yes, Old Rusty Cars Differences 3 includes a 'Hint' button that can help guide you when you're stuck finding the differences between the two images.

Old Rusty Cars Differences 3 adjusts its difficulty dynamically based on your performance, offering a challenge that suits your skill level as you progress.

Progress saving features are not mentioned in the game description, so it's best to complete each session in one go or check for autosave features within the game.

Old Rusty Cars Differences 3 features images of vintage, weathered cars, providing a nostalgic look at classic automobiles.

The game description does not mention any multiplayer mode, so it seems that Old Rusty Cars Differences 3 is designed for single-player gameplay.