If the extraction asks for "Volume 2," it means part2.rar is missing from the folder.
Some indie games are flagged as "False Positives." If the .exe disappears, check your antivirus quarantine.
If you are updating from version 0.1.x, you can usually find your save files in the game/saves folder or the %AppData% directory and move them to the new version's folder. If you'd like, I can help you with: Finding the official developer page for updates.