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Version: 1.3.0
Download use: GOG Downloader, gogdownloader://slime_rancher/installer_win_en
Result: only first 126,405,279 bytes of setup_slime_rancher_1.3.0_(32bit)_(22291).exe downloaded
GOG Downloader reports "Checksum error on chunk 12, please contact support!"

Trying HTTP download right now, but it's quite slow.
HTTP download seems fine. Both have valid digital signature.