Sorry, you can't download DigitalOcean Snapshots
Unfortunately, you are unable to download your DigitalOcean snapshots and backups outside of the DigitalOcean environment. They have not made this feature available.
In 2013 DigitalOcean released a press release downloading snapshots on their road map however in 2022 it's still not possible.
You can do a lot with DigitalOcean snapshots within their network. Create new droplets from Snapshot, restore existing droplets to snapshot and move snapshot across data centres.
Alternatives
When SnapShooter was released in 2017 we had no alternative however in 2020 we decided to branch into supporting a range of backups that allow you to download/export your data, to whatever storage you want.
If you want to backup your file system in a way you can download it we offer a file backup service as well as a server cloning backup (experimental)
Database Backups
File Backups