Basically people buy the GOG version which is DRM free. They strip it from the installer, upload it to Amazon and sell it way below the MSRP >Amazon, has been

Basically people buy the GOG version which is DRM free. They strip it from the installer, upload it to Amazon and sell it way below the MSRP >Amazon, has been selling pirated copies of PC games, some do-gooders have discovered (or rather, sellers using Amazon as a storefront have been selling the pirate goods). The dodgy games include icy societal survival game Frostpunk and dusty martian city-builder Surviving Mars, which were being sold for the suspiciously cheapo prices of $3 and $4. If you bought one of these games, you got an illegitimate installer to download, which contained some files ripped from GOG store versions of the games.