1. It doesnt matter.
2. As far as I am aware of no.
This version was just put up for sale for people who still wanna play the legacy (classic) version of the game, which is maintained by the OG developer Michael and was not purchasable anymore because of issues with another payment company until now.
The upcoming steam version (v10.0) is developed by another person.
If you rather wanna play the steam version I would suggest waiting for a bit the release is right around the corner and skip this classic version unless ofc you have the funds to buy both versions.